UC-NRLF 


o 


UNIVERSITY  FARM 


6 


DAIRY  LABORATORY 
GUIDE 


By 

G.  L.  MARTIN 
Professor  of  Dairying,  North  Dakota  Agricultural  College 


UNIVERSITY  OF  CALIFORNIA 

LIBRARY 

BRANCH  OF  THE 
COLLEGE  OF  AGRICULTURE 


1913 

EBB  PUBLISHING 

ST.E'MJL.MINN. 


COPYRIGHT,     1913 

BY 

WEBB  PUBLISHING  COMPANY 


PREFACE 


This  laboratory  guide  is  designed  to  give  the  beginning 
dairy  student  a  few  suggestions  in  the  study  of  the  produc- 
tion and  care  of  milk,  and  the  testing,  manufacturing,  and 
marketing  of  dairy  products.  It  is  the  outgrowth  of  a 
demand  from  dairymen,  creamerymen,  and  high  school, 
short  course,  and  college  students  for  a  guide  in  the  practical 
application  of  modern  dairy  science. 

It  will  be  quite  necessary  to  supplement  these  exercises 
with  text-book  references  in  order  that  the  student  may  gain 
a  thorough  knowledge  of  the  underlying  principles  of  dairy- 
ing. A  grasp  of  the  fundamental  principles  in  each  exercise 
herein  followed  out  systematically  and  applied  in  practice  is 
bound  to  bring  results. 

The  writer  is  indebted  to  the  Creamery  Package  Manu- 
facturing Company  and  the  J.  G.  Cherry  Company  for  a 
number  of  the  cuts  used  in  this  book. 


G.  L.  MARTIN. 


North  Dakota  Agricultural  College, 
January  1;  1913, 


TABLE  OF  CONTENTS 


PART  ONE.     The  Production  and  Care  of  Dairy  Products 

Page 

Exercise     1.  Microscopic  Examination  of  Milk 8 

Exercise    2.  The  Physical  Differences  of  Milk  and  Its  Products.  10 

Exercise    3.  Effects  of  Adding  Chemicals  to  Dairy  Products ....  12 

Exercise    4.  The  Purity  of  Market  Milk  and  Cream 14 

Exercise    5.  The  Source  of  Fermentations  in  Dairy  Products.  ...  16 

Exercise    6.  Lactic  Acid  in  Dairy  Products , 18 

Exercise     7.  Influence  of  Barn  Ventilation  on  Dairy  Products ...  22 

Exercise    8.  Cleanliness  and  the  Keeping  Quality  of  Milk 24 

Exercise    9.  Temperature  and  the  Keeping  Quality  of  Milk.  ...  2o 

Exercise  10.  Efficiency  of  Methods  of  Cooling  Milk  and  Cream.  .  28 

Exercise  11.  Open  and  Covered  Containers  for  Dairy  Products.  .  30 

Exercise  12.  Absorbing  Capacity  of  Dairy  Products 32 

Exercise  13.  Effects  of  Impure  Water  upon  Dairy  Products.  ...  34 

Exercise  14.  Determination  of  Moisture  in  Dairy  Products 36 

Exercise  15.  Determination  of  Salt  in  Dairy  Products 38 

Exercise  16.  Tests  for  Renovated  Butter  and  Margarine 40 

PART  TWO.    The  Testing  of  Dairy  Products 

Exercise     1 .  Operation  of  the  Babcock  Test 48 

Exercise    2.  Mixing  Milk  and  Acid  for  Testing 50 

Exercise    3.  Varying  the  Amount  of  Acid  in  Testing 52 

Exercise    4.  Temperature  of  the  Water  in  Testing 54 

Exercise    5.  Testing  Skimmilk,   Buttermilk,   and  Whey 56 

Exercise    6.  Testing  Cream 58 

Exercise    7.  Measuring  and  Weighing  Cream 60 

Exercise    8.  Speed  of  the  Babcock  Tester 62 

Exercise    9.  Temperature  in  Reading  the  Tests 64 

Exercise  10.  Testing  Cheese 66 

Exercise  11.  Determining  the  Butter-fat  in  Butter 68 

Exercise  12.  Testing  Condensed  Milk 70 

Exercise  13.  Specific  Gravity  of  Milk 72 


CONTENTS. 


PART  THREE.    The  Manufacture  of  Dairy  Products 

Page 

Exercise     1.  Examination  of  Hand  Separators 78 

Exercise    2.  Flushing   the   Separator 80 

Exercise    3.  Washing   the   Separator 82 

Exercise    4.  Temperature  of  the  Milk  for  Separation 84 

Exercise    5.  Speed  of  the  Separator 86 

Exercise    6.  Changing  the  Cream  Screw  on  the  Separator 88 

Exercise    7.  Comparison  of  Various  Methods  of  Creaming 90 

Exercise    8.  Influence  of  Acidity  on  the  Churnability  of  Cream.  96 

Exercise    9.  Effects  of  Temperature  in  Churning 98 

Exercise  10.  Variations  in  Temperature  of  Wash  Water  on  Butter  100 

Exercise  11.  The  Distribution  of  Salt  in  Butter 102 

Exercise  12.  The  Effect  of  Overworking  Butter 104 

Exercise  13.  Influence  of  the  Grade  of  Cream  on  Quality  of  Butter  106 

PART  FOUR.    The  Marketing  of  Dairy  Products 

Exercise    1.  Variation  of  Butter-fat  in  Market  Milk 110 

Exercise    2.  Variation  of  Butter-fat  in  Market  Cream 112 

Exercise    3.  Marketing  Butter  and  By-products 114 

Exercise    4.  The  Marketing  of  Ice  Cream 116 

Exercise    5.  The  Standardizing  of  Dairy  Products 118 

Exercise    6.  The  Determination  of  Creamery  Dividends 121 

Appendix.  The  Scoring  of  Butter 123 

Standards  for  Milk  and  Milk  Products 130 

Composition  of  Dairy  Products  and  By-Products .  . .  133 

Index . .  .136 


PART  ONE 


THE  PRODUCTION  AND  CARE  OF  DAIRY  PRODUCTS 

The  trend  of  modern  farm  management  is  to  put  each 
separate  enterprise  upon  a  sound  business  basis.  The  dairy- 
man is  fortunate  in  having  perfected  an  accurately  detailed 
system  which  enables  him  to  detect  the  smallest  leak  in  the 
business  anywhere  from  the  time  the  milk  leaves  the  cow 
until  it  is  sold  as  a  finished  product.  In  order  to  insure  a  fair 
margin  of  profit,  he  needs  to  produce  at  the  lowest  cost,  in- 
crease the  output  of  each  cow  to  the  maximum,  and  utilize  all 
of  the  by-products  to  advantage. 

The  first  problem  before  the  student  of  dairy  science  is 
to  study  the  best  methods  of  production  and  care  of  milk 
and  cream  on  the  farm.  This  end  of  the  business  is  essen- 
tially the  most  difficult  to  perfect,  owing  to  the  widely  vary- 
ing conditions,  and  needs  a  close  study  of  the  technicalities  of 
dairy  science  applied  in  a  practical  way  to  actual  conditions. 


8  DAIRY  LABORATORY  GUIDE 

EXERCISE  1 

MICROSCOPIC  EXAMINATION  OP  MILK 

Object :  To  examine  microscopically  milk  from  different 
breeds  of  cows. 

Apparatus:     Samples  of  milk,  and  microscope. 

Steps:  1.  Place  a  drop  of  milk  upon  a  microscope  slide 
and  examine. 

2.  Dilute  the  sample  of  milk  with  an  equal  quantity  of 
distilled  water;  then  prepare  a  slide  of  the  same. 

3.  Make  drawings  of  the  field  for  each  sample  and  note 
the  character  of  the  impurities. 


Breed 

Jersey 

Guernsey 

Aryshire 

Holstein 

Drawing 

Impurities 

Application:     1.     In   what   particular    do    the   samples 
differ? 

2.  What  part  of  the  milk  contains  the  coloring  matter? 

3.  How  do  the  fat  globules  compare  in  size,  shape,  and 
number? 

4.  How  does  the  milk  from  the  different  breeds  compare 
as  to  color? 


DAIRY  LABORATORY  GUIDE 

Student's  Notes: 


10 


DAIRY  LABORATORY  GUIDE 


EXERCISE  2 


THE    PHYSICAL  DIFFERENCES    BETWEEN    MILK    AND    ITS 
PRODUCTS 

Object:  To  determine  the  physical  difference  micro- 
scopically between  whole  milk,  cream,  skimmilk,  and  colos- 
trum, when  heated  and  cooled. 

Apparatus :     Samples  to  be  examined  and  microscope. 

Steps:  1.  Place  a  drop  of  each  sample  upon  a  slide  and 
examine. 

2.  Heat  the  slide  gradually  and  reexamine. 

3.  Cool  the  slide  gradually  and  reexamine. 

4.  Diagram  the  field  in  each  case  and  record  all  findings. 

Data: 


Normal 

Heated 

Cooled 

Milk 

Cream 

Skimmilk 

Colostrum 

Application :     1.     In  what  manner  do  the  various  samples 
differ? 

2.  What  is  the  effect  of  heat  upon  the  samples? 

3.  How  does  cold  affect  the  samples? 


DAIRY  LABORATORY  GUIDE  11 

Student's  Notes: 


12  DAIRY  LABORATORY  GUIDE 

EXERCISE  3 

EFFECTS  OF  ADDING  CHEMICALS  TO  DAIRY  PRODUCTS 

Object:  To  determine  the  physical  effects  of  adding 
chemicals  to  milk,  cream,  skimmilk,  and  pasteurized  milk. 

Apparatus:    Samples  to  be  examined  and  a  microscope. 

Steps:  1.  Place  a  drop  of  milk  upon  a  slide  and  then 
add  a  drop  of  dilute  acid. 

2.  Place  a  drop  of  milk  upon  a  second  slide  and  add  a 
drop  of  dilute  rennet  extract. 

3.  Place  a  drop  of  milk  upon  a  third  slide  and  add  a  drop 
of  ether. 

4.  Prepare  samples  of  cream,  skimmilk,  and  whey  in  the 
same  manner. 

5.  Diagram  the  field  each  time  before  and  after  applying 
the  chemical  agent. 

Data: 


Acid 

Rennet 

Ether 

Milk 

Cream 

Skimmilk 

Pasteurized  milk 

Application:  1.  What  particular  constituents  of  milk 
are  affected  by  the  acid?  By  the  rennet?  By  the  ether? 

2.  In  what  way  is  pasteurized  milk  affected  by  these 
agents? 


DAIRY  LABORATORY  GUIDE  13 

Student's  Notes: 


14  DAIRY  LABORATORY  GUIDE 

EXERCISE  4 

THE  PURITY  OF  MARKET  MILK  AND  CREAM 

Object:  To  determine  the  purity  of  market  milk  and 
cream  with  reference  to  the  amount  of  suspended  dirt  present. 

Apparatus:  Samples  of  milk,  cream,  and  skimmilk;  sedi- 
ment tester;  and  pint  jars. 

FILTER  METHOD 

Steps :  1.  Secure  a  pint  of  unstrained  milk  from  a  com- 
mon milk  pail,  and  filter.  Remove  the  cotton  disks  and  dry 
on  blotting  paper  or  on  a  warm  surface.  Examine  with  a 
reading  glass  and  record  the  findings. 

2.  Secure  a  sample  of  milk  from  a  small-top  milk  pail  to 
test  its  sanitary  efficiency. 

3.  Test  the  efficiency  of  different  kinds  of  strainers  by 
filtering  samples  of  milk  after  straining  through  an  ordinary 
wire  strainer,  a  cotton  strainer,  or  a  cheesecloth  strainer. 


Fig.   1.     Sediment  tester. 


4.  Test  the  efficiency  of  a  hand  separator  in  removing 
suspended  dirt  by  filtering  a  pint  of  milk  before  separating; 
then  filtering  samples  of  the  cream  and  the  skimmilk  after 
separation. 

GRAVITY  METHOD 

Steps :  1.  After  stirring  the  milk  well,  take  samples  and 
put  into  covered  glass  cylinders  or  bottles  and  set  aside 
undisturbed  for  a  short  time. 

2.  To  examine,  raise  the  cylinder  carefully  to  a  position 
even  with  the  eye;  then  look  for  sediment  in  the  bottom, 


DAIRY  LABORATORY  GUIDE 


15 


This  method  is  of  little  value  except  in  cases  of  much  sedi- 
ment. 

Data: 


Filter 

Gravity 

Amount 

Character 

Application :     1.     What  practical  application  can  be  made 
of  sediment  tests? 

2.  What  percentage  of  the  sediment  in  milk  remains 
undissolved? 

3.  What  is  the  influence  of  sanitary  milk  pails  upon  the 
purity  of  market  milk  according  to  the  above  tests? 

Student's  Notes: 


16  DAIRY  LABORATORY  GUIDE 

EXERCISE  5 

THE  SOURCE  OF  FERMENTATIONS  IN  DAIRY  PRODUCTS 

Object:  To  note  the  effects  of  undesirable  fermentations 
in  milk  and  to  determine  their  source  by  means  of  the  Wiscon- 
sin curd  test. 

Apparatus:  Samples  of  milk,  pint  jars  with  covers, 
rennet,  extract,  thermometer,  knife,  and  warming  tank. 

Steps:  1.  Number  the  jars  and  sterilize  them  thor- 
oughly. 

2.  Fill  each  jar  about  half  full  of  the  milk  and  then  place 
them  in  the  water  bath. 

3.  Heat  the  water  until  the  samples  reach  a  temperature 
of  100  degrees  F.;  then  add  ten  drops  of  rennet  to  each  and 
mix  thoroughly. 

4.  After  the  milk  has  curdled,  allow  it  to  stand  for  a  few 
minutes  and  settle;  then  cut  into  small  pieces  and  drain  off 
the  whey. 

5.  Cover  the  j  ars  and  replace  them  in  the  bath  for  several 
hours  at  the  regular  temperature. 

6.  Examine  the  samples  for  odor,  flavor,  and  appearance 
of  curd  at  short  intervals  for  several  hours;  then  allow  to 
stand  for  a  few  days  and  reexamine. 

7.  Care  is  necessary  in  every  detail  of  this  test  to  keep 
the  temperature  of  the  samples  uniform  and  to  prevent  con- 
tamination. 

Application :  1.  How  do  the  samples  of  milk  differ  as  to 
appearance  of  curd? 

2.  How  do  the  appearance  of  the  curd  and  the  char- 
acter of  its  flavor  correspond? 

3.  To  what  are  pin  holes  due? 


DAIRY  LABORATORY  GUIDE 


17 


4.  How  may  they  be  distinguished  from  mechanical 
holes? 

5.  What  practical  application  may  be  made  of  this  test? 

Data: 


Time 

1 

2 

3 

4 

5 

6 

24  hrs. 

Appearance  of  curd 

48  hrs. 

24  hrs. 

Odor 

48  hrs. 

24  hrs. 

Flavor 

48  hrs. 

Student's  Notes: 


18  DAIRY  LABORATORY  GUIDE 

EXERCISE  6 

LACTIC  ACID  IN  DAIRY  PRODUCTS 

Object:  To  determine  the  percentage  of  lactic  acid  in 
dairy  products  according  to  various  methods. 

MANNS'  TEST 

Apparatus:  Samples  of  whole  milk,  skimmilk,  butter- 
milk, cream,  butter,  whey,  and  starter;  Manns'  testing  outfit. 

Preparing  the  Alkali  Solution.  The  best  way  to  do, 
where  the  facilities  are  not  at  hand  for  standardizing,  is  to 
secure  at  the  drug  store  a  quantity  of  standard  solution  of 
sodium  hydroxide;  then  dilute  it  to  N/10  as  needed.  This 
can  be  done  by  putting  100  c.  c.  of  the  standard  solution  into 
a  liter  flask  and  filling  to  the  1000  c.  c.  mark  with  distilled 
water  or  with  soft  water. 

Preparing  the  Indicator.  Obtain  a  small  quantity  of  the 
compound  phenolphthalein  at  the  drug  store;  then  dissolve 
1  gram  of  the  dry  powder  in  30  c.  c.  of  90%  alcohol.  It  is 
necessary  to  use  only  a  few  drops  at  a  time. 

Steps:  1.  Put  50  c.  c.  of  the  sample  to  be  tested  into 
the  white  cup;  then  add  a  few  drops  of  the  phenolphthalein 
indicator. 

2.  Add  the  N/10  alkali  solution  from  the  burette  drop 
by  drop  until  a  permanent  pink  color  appears. 

3.  One  c.  c.  of  N/10  alkali  solution  contains  .004  grams 
of  sodium  hydroxide,  which  is  sufficient  to  neutralize  .009 
grams  of  pure  lactic  acid.     Read  from  the  burette  the  num- 
ber of  c.  c.  of  alkali  used  and  substitute  in  the  formula. 

Formula: 

c.c.   alkali  used  X  .009 

X  100  =  percentage  of  acid. 

c.  c.  of  sample 


DAIRY  LABORATORY  GUIDE 


19 


FERRINGTON  TEST 

Apparatus :  Samples  to  be  tested,  100  c.  c.  graduate,  white 
cup,  Ferrington's  alkaline  tablets,  and  a  17.5  c.  c.  pipette. 

Preparation  of  Alkali  Solution.  Dissolve  five  of  the  pre- 
pared tablets  in  97  c.  c.  of  warm,  preferably  distilled,  water 
or  soft  water.  Keep  in  a  tightly  stoppered  bottle  when  not 
in  use.  It  is  necessary  to  prepare  a  fresh  solution  frequently, 
as  it  will  lose  its  strength  within  a  few  days. 

Steps:  1.  With  a  pipette  transfer  to  a  white  cup  17.5 
c.  c.  of  the  sample  to  be  tested;  then  add  the  alkali  from  a 
graduate  or  from  a  burette  until  a  permanent  pink  color 
remains. 

2.  In  reading  the  results,  the  number  of  c.  c.  of  the  alka- 
line solution  required  to  bring  the  permanent  pink  color  indi- 
cates the  number  of  hundredths  of  one  per  cent  of  acid  present. 
For  instance,  if  25  c.  c.  of  alkali  are  required,  it  indicates  that 
.25%  of  acid  is  present. 

Data: 


Manns 

Ferrington 

Sample 

C.  C.  alk. 

Per  cent 

C.  C.  alk. 

Per  cent 

Milk 

Skimmilk 

Buttermilk 

Cream 

Butter 

Whey 

Starter 

Cheese 

20  DAIRY  LABORATORY  GUIDE 

Application:     1.     What  is  the  object  in  making  up  the 
alkali  solution  from  soft  water  or  from  distilled  water? 

2.  What  causes  the  pink  color  to  appear? 

3.  Why  should  the  Ferrington  tablets  be  kept  dry? 

4.  What  effect  has  standing  upon  the  tablet  solution? 

Student's  Notes: 


DAIRY  LABORATORY  GUIDE 


21 


Fig.  2.    A  farmer's  dairy  room  and  equipment*  showing  an  economical 
of  power. 


22 


DAIRY  LABORATORY  GUIDE 


EXERCISE  7 

INFLUENCE  OF  BARN  VENTILATION  ON  DAIRY  PRODUCTS 

Object:  To  determine  the  influence  of  barn  ventilation 
upon  the  purity  and  keeping  quality  of  market  milk. 

Apparatus:  Samples  of  milk,  covered  pint  jars,  ther- 
mometer, and  acid  testing  outfit. 

Steps :  1 .  Secure  samples  of  milk  from  a  stable  equipped 
with  a  good  ventilating  system,  and  from  another  stable  with 
no  provision  for  ventilation. 

2.  Test  the  samples  in  each  set  for  acidity;  then  strain 
the  milk  through  sterile  cheesecloth. 

3.  Sterilize  a  number  of  glass  jars  and  then  transfer  the 
milk  to  the  jars  and  cover  tightly. 

4.  Set  the  samples  in  a  place  that  can  be  kept  at  a  con- 
stant temperature  of  about  70°  F. 

5.  Examine  one  jar  in  each  set  at  intervals  and  test  for 
odor,  flavor,  and  acidity. 

6.  Keep  one  jar  in  each  set  unopened  and  note  the 
appearance  of  curd.     Always  use  a  sterilized  pipette  in  exam- 
ining the  samples. 

Data: 


Ventilated 

Not  ventilated 

Hours 

24 

48 

72 

24 

48 

72 

Odor 

Flavor 

Temperature 

Acidity 

Grade 

Market  value 

DAIRY  LABORATORY  GUIDE  23 

Application:  1.  Which  sample  had  the  cleanest  odor 
and  flavor  when  set? 

2.  How  did  the  two  sets  of  samples  compare  as  to  rapid- 
ity of  development  of  flavor?  Of  acid?  Of  odor? 

Student's  Notes: 


24 


DAIRY  LABORATORY  GUIDE 


EXERCISE  8 

CLEANLINESS  AND  THE  KEEPING  QUALITY  OF  MILK 

Object:  To  determine  the  effects  of  cleanliness  upon 
the  keeping  quality  of  milk. 

Apparatus :  Samples  of  milk,  covered  pint  jars,  thermom- 
eter, acid  testing  outfit,  and  sediment  tester. 

Steps:  1.  Secure  the  following  samples  of  milk:  from 
clean  stables,  from  dirty  stables,  strained,  unstrained,  from 
wagon,  and  pasteurized  milk. 

2.  Test  each  sample  for  acidity  and  sediment. 

3.  Sterilize  six  glass  jars  and  number  them  from  1  to  6. 

4.  Pasteurize  a  sample  of  milk  at  140°  F.  for  15  minutes. 
Have  cap  jars. 

5.  Fill  a  jar  with  each  of  the  samples;  then  cover 
tightly  and  set  at  60°  F. 

6.  Examine  each  jar  at  intervals  of  24  hours  and  test 
for  acidity,  odor,  and  flavor. 

7.  Note  the  length  of  the  time  required  to  curdle  and  the 
appearance  of  curd  from  each  sample. 

Data: 


Sample 

"  Clean 
stable 

Dirty 
stable 

Strained 

Un- 
strained 

Wagon 

Pasteur- 
izod 

Sediment 

Odor 

Flavor 

Acidity 

24  hrs. 

48  hrs. 

72  hrs. 

DAIRY  LABORATORY  GUIDE 


25 


Application:     1.     Which    sample    showed    the    greatest 
amount  of  acid  when  set? 

2.  How  did  the  amount  of  sediment  affect  the  flavor? 

3.  How  did  the  pasteurized  sample  compare  in  flavor 
with  the  rest? 


Fig.  3.     Covered  milk  pails. 

Student's  Notes: 


DAIRY  LABORATORY  GUIDE 


EXERCISE  9 

TEMPERATURE  AND  THE  KEEPING  QUALITY  OF  MILK 

Object :  To  determine  the  effect  of  temperature  upon  the 
keeping  quality  of  milk. 

Apparatus:  Samples  of  freshly  drawn  milk,  sample  jars, 
thermometers,  and  acid  testing  outfit. 

Steps:  1.  Wash  six  sample  jars  thoroughly;  then  dry 
and  number  them  from  1  to  6. 

2.  Test  the  milk  for  odor,  flavor,  and  acidity. 

3.  Fill  the  sample  jars,  cover  each  with  a  small  piece  of 
cheesecloth,  and  set  them  at  90°,  70°,  and  50°  F.,  respectively. 
Have  arrangements  to  keep  the  temperature  reasonably  uni- 
form.    A  fireless  cooker  well  insulated  will  answer  the  pur- 
pose well.     Always  have  as  nearly  farm  conditions  as  possible. 

4.  Record  the  time  of  setting  the  samples;  then  examine 
them  regularly  at  intervals  of  24  hours. 

Data: 


Temperature 

90° 

70° 

50° 

Hours 

24 

48 

72 

24 

48 

72 

24 

48 

72 

Odor 

Flavor 





— 





— 



Acidity 

Grade 

— 

Market  value 

Application:  1.  At  which  temperature  does  the  acid 
develop  the  most  rapidly? 

2.  What  are  the  effects  of  temperature  on  the  odor?  On 
the  flavor?  On  the  appearance  of  the  curd? 


DAIRY  LABORATORY  GUIDE  27 

3.  Compute  the  value  of  returns  in  one  year  from  5000 
Ibs.  of  3%  milk,  containing  405  Ibs.  of  cheese. 

4.  Figure  from  findings  after  12  hours  and  use  current 
prices  for  various  grades  of  Cheddar  cheese. 

Student's  Notes: 


28  DAIRY  LABORATORY  GUIDE 

EXERCISE  10 

EFFICIENCY  OF  METHODS  OF  COOLING  MILK  AND  CREAM 

Object:  To  determine  the  variation  in  quality  of  cream, 
when  cooled  and  kept  at  room  temperature,  when  set  in  water, 
and  when  cooled  in  a  refrigerator. 

Apparatus :  A  small  quantity  of  milk  and  freshly  sepa- 
rated cream,  acid  testing  outfit,  thermometers,  six  pint  bottles 
or  containers,  and  a  piece  of  cheesecloth. 

Steps:  1.  Secure  samples  of  fresh  milk  and  cream,  and 
test  them  for  acidity,  odor,  and  flavor. 

2.  Number  the  bottles  in  sets  1,  2,  and  3;  then  measure 
out  three  bottles  of  milk  and  three  of  cream.     Cover  each 
with  a  piece  of  cheesecloth. 

3.  Place  set  No.  1  in  the  open  at  the  ordinary  room  tem- 
perature.    Place  set  No.  2  in  cold  running  water,  if  possible. 
Place  set  No.  3  in  a  refrigerator. 

4.  Examine  the  samples  at  frequent  intervals,  not  to 
exceed  twelve  hours,  and  record  all  data. 

Rules  for  Grading  Cream. 

First  Grade:  All  sweet  cream  of  clean  odor  and  flavor, 
with  not  to  exceed  .2%  of  acidity. 

Second  Grade:  All  sour  cream  reasonably  clean  in  odor 
and  flavor,  with  not  to  exceed  .8%  of  acidity. 

Application:  1.  Determine  from  data  whether  the  but- 
ter made  from  such  cream  would  grade  Extra,  First,  or  Second. 

2.  How  much  butter  can  be  made  in  one  year  from  a  cow 
giving  5000  Ibs.  of  3%  milk,  allowing  16%  O.  R.? 

3.  What  will  the  butter  be  worth  at  current  quotations 
for  the  various  grades? 


DAIRY  LABORATORY  GUIDE 


29 


Data: 


Room 

Water 

Refrigerator 

Samples 

Milk 

Cream 

Milk 

Cream 

Milk 

Cream 

Hours 

24 

36 

48 

24 

36 

48 

24 

36 

48 

24 

36 

48 

24 

36 

48 

24 

36 

48 

Odor 

Flavor 

Acidity 

Temp. 

Grade 

Market 
value 

Student's  Notes: 


30 


DAIRY  LABORATORY  GUIDE 

EXERCISE  11 


.  OPEN  AND  COVERED  CONTAINERS  FOR  DAIRY  PRODUCTS 

Object:  To  determine  the  effects  upon  quality  of 
keeping  milk  and  cream  in  open  and  covered  containers. 

Apparatus:  Samples  of  milk  and  cream,  jars,  thermom- 
eter, acid  tester,  and  Babcock  testing  outfit. 

Steps:  1.  Obtain  two  pints  of  milk  warm  from  the 
cow  and  two  pints  of  cream  immediately  after  separating. 

2.  Arrange  the  bottles  in  sets  of  two,  with  milk  in  bottles 
1  and  cream  in  bottles  2.     Leave  one  set  open  and  cover 
the  second  set  with  tight-fitting  covers. 

3.  Set  the  samples  aside  at  ordinary  room  temperature 
and  examine  at  intervals  for  odor,  flavor,  and  acidity. 

4.  Secure  two  Mason  jars  or  two  milk  cans  with  tight-fit- 
ting covers.     Wash  them  perfectly  clean  by  ordinary  methods 
and  then  cover  one  tightly  and  leave  the  other  open.     Exam- 
ine them  after  a  few  hours  and  note  the  odor  when  removing 
the  cover. 

Data: 


Open 

Covered 

Samples 

Milk 

Cream 

Milk 

Cream 

Hours 

12 

24 

36 

48 

12 

24 

36 

48 

12 

24 

36 

48 

12 

24 

36 

48 

Odor 

Flavor 

Acidity 

Grade 

Market 
value 

DAIRY  LABORATORY  GUIDE  31 

Application:     1.     What   effect   has    covering   upon   the 
development  of  odors?     Flavors? 

2.  Which  sample  developed  acid  the  most  rapidly? 

3.  How  would  the  covering  of  warm  cream  influence  its 
market  value? 

Student's  Notes: 


DAIRY  LABORATORY  GUIDE 


EXERCISE  12 

ABSORBING  CAPACITY  OF  DAIRY  PRODUCTS 

Object:  To  determine  the  capacity  of  dairy  products  to 
absorb  odors  and  flavors  from  their  surroundings. 

Apparatus:  Several  samples  each  of  first-grade  milk, 
cream,  and  butter. 

Steps:  1.  Thoroughly  clean  and  sterilize  8  pint  jars; 
then  divide  these  into  two  sets  and  number  them  from  1  to  4. 

2.  Fill  one  set  of  the  bottles  with  milk,  and  the  other  set 
with   cream. 

3.  Secure  several  pound  prints  of  butter  and  place  them 
in  open  containers. 

4.  Make  up  four  lots  containing  a  sample  each  of  milk, 
cream,  and  butter;  then  number  the  sets  from  1  to  4. 

5.  Place  lot  No.  1  in  close  proximity  to  corn  silage,  lot 
No.  2  in  a  vegetable  cellar,  lot  No.  3  in  a  closed  icebox  con- 
taining other  foods,  and  lot  No.  4  in  close  proximity  to  cooked 
cabbage,  onions,  or  other  vegetables. 

6.  Examine  the  samples  at  intervals  and  note  the  changes 
which  take  place  in  the  odors  and  flavors. 

Data: 


Lot 

1 

2 

3 

4 

Samples 

Milk 

Cr. 

But. 

Milk 

Cr. 

But. 

Milk 

Cr. 

But. 

Milk 

Cr. 

But. 

Odor 

Flavor 

Grade 

Market 
value 

DAIRY  LABORATORY  GUIDE  33 

Application:     1.     Which    sample    absorbs    corn    silage 
flavors  most  readily? 

2.  At  what  time  would  dairy  products  be  likely  to 
acquire  the  flavor  of  silage? 

3.  How  are  dairy  products  influenced  by  being  kept  in 
the  cellar?     In  a  closed  icebox   with  other   food?    In   the 
kitchen? 

4.  How  does  the  flavor  of  milk  and  cream  influence  its 
market  value? 

Student's  Notes: 


34  DAIRY  LABORATORY  GUIDE 

EXERCISE  13 

EFFECTS  OF  IMPURE  WATER  ON  DAIRY  PRODUCTS 

Object:  To  determine  the  effect  of  impure  water  upon 
the  quality  of  milk,  when  the  water  is  added  or  used  for 
washing  the  utensils. 

Apparatus:  Samples  of  fresh  milk,  four  covered  jars, 
incubator,  and  thermometer. 

Steps:  1.  Sterilize  the  glass  jars  by  placing  them  in  a 
water  bath;  then  gradually  raise  the  water  to  a  boiling  tem- 
perature. 

2.  Remove  the  jars  and  invert  them  upon  a  clean  surface 
to  cool. 

3.  Fill  jar  No.  1  with  milk  for  a  check  sample. 

4.  Add  10  c.  c.  of  impure  water  to  jar  No.  2;  then  fill  with 
milk. 

5.  Fill  jar  No.  3  with  milk,  pasteurized  at  145°  F.  for 
fifteen  minutes. 

6.  Rinse  jar  No.  4  with  impure  water  and  then  fill  with 
milk. 

7.  Cover  all  the  jars  tightly;  then  set  them  into  an  incu- 
bator and  hold  at  70°  F. 

8.  Examine  at  intervals  and  record  all  data. 

• 

Application:  1.  How  do  the  odors  and  flavors  of  the 
different  lots  compare? 

2.  Which  samples  show  the  effect  of  impure  water? 

3.  How  can  the  presence  of  objectionable  odors   and 
flavors  be  accounted  for  in  the  various  samples? 


DAIRY  LABORATORY  GUIDE 


35 


Data: 


Sample 

1 

2 

3 

4 

Hours 

24 

48 

7, 

24 

48 

JO) 

24 

48 

72 

24 

48 

72 

Odor 

Flavor 



Acidity 

Grade 

Market 
value 

Student's  Notes: 


36 


DAIRY  LABORATORY  GUIDE 


EXERCISE  14 

DETERMINATION  OF  MOISTURE  IN  DAIRY  PRODUCTS 

Object:  To  determine  the  percentage  of  moisture  in 
dairy  products. 

Apparatus :  Samples  to  be  tested,  torsion  balance,  beaker 
and  flame. 

Steps :  1 .  Transfer  a  sample  of  butter  to  a  beaker ;  then 
heat  gently  by  setting  the  beaker  into  a  waterbath  until  the 
butter  softens  to  the  consistency  of  cream. 

2.  Balance  the  cup  on  the  scales  and  weigh  out  10  grams 
of  the  sample. 

3.  Heat  gently  over  the  flame  until  all  of  the  moisture  is 

removed;  then  reweigh  and  re- 
cord the  percentage  of  moisture. 

4.  Precaution    is     neces- 
sary not  to  heat  too  rapidly 
nor  overheat,  as   the  volatile 
fats  may  escape.    Stop  heating 
when  the  casein  film  of  small 
bubbles  over  the  butter  rises 
well  up  in  the  cup  and  just 
before  the  brown  color  appears 

I  in  the  butter. 

5.  To  avoid  overheating, 
I  it  is  well  to  temper  the  heat 
|  by  placing   the  sample   in  a 
|  steam  oven,  in  a  bath,  or  by 

placing  an  asbestos  mat  be- 
tween the  flame  and  the  con- 
Fig.  4.    Ames  moisture  test. 


DAIRY  LABORATORY  GUIDE 


37 


Data: 


Butter 

Unsalted  butter 

Margarine 

Cheese 

1 

2 

3 

Application:     1.     What  is  the  legal  standard  limit  of 
moisture  in  butter? 

2.  Of  what  importance  is  the  presence  of  moisture  in 
butter? 

3.  Where  does  the  moisture  come  from  in  dairy  products? 

Student's  Notes: 


38  DAIRY  LABORATORY  GUIDE 

EXERCISE  15 

DETERMINATION  OF  SALT  IN  DAIRY  PRODUCTS 

Object:  To  determine  the  percentage  of  salt  in  dairy 
products. 

Apparatus:  Samples  to  be  tested,  torsion  balance, 
beaker,  flask,  burette,  and  N/10  silver  nitrate  solution. 

Preparation  of  Silver  Nitrate  Solution.  In  case  no  N/10 
normal  silver  nitrate  solution  is  at  hand,  obtain  from  the 
drug  store  an  ounce  of  chemically-pure  silver  nitrate  crystals. 
Weigh  out  1.69  of  the  crystals  and  dissolve  them  in  100  c.  c.  of 
distilled  water  or  in  pure  soft  water,  when  it  is  ready  for  use. 
The  silver  nitrate  is  readily  affected  by  sunlight;  so  it  is  best 
kept  in  a  glass-stoppered,  preferably  brown  glass,  bottle,  so  it 
will  not  lose  strength. 

Preparing  Indicator.  The  indicator  used  is  potassium 
chromate.  An  ounce  of  chemically-pure  chromate  obtained 
from  the  drug  store  and  dissolved  in  100  c.  c.  of  distilled  water 
or  pure  soft  water  will  make  up  a  sufficient  amount  to 
last  indefinitely. 

Steps :  1.  Weigh  out  10  grams  of  butter  in  a  beaker  the 
same  as  in  the  moisture  determination. 

2.  Melt  the  butter  and  transfer  to  a  250  c.  c.  stoppered 
flask.     Rinse  the  beaker  with  warm  water  several  times  and 
transfer  to  the  flask. 

3.  Fill  the  flask  to  the  250  c.  c.  mark  with  warm  water 
and  shake  thoroughly  until  all  of  the  salt  is  dissolved.    Allow 
the  flask  to  stand  quiet  for  a  short  time  until  the  butter- 
fat  has  collected  on  the  surface  and  then  remove  it  by  means 
of  a  pipette. 

4.  Transfer  17.5  c.  c.  of  the  solution  with  a  pipette  to  a 
white  cup;  then  add  a  drop  of  the  potassium  chromate 
indicator. 


DAIRY  LABORATORY  GUIDE 


39 


5.  Add  N/10  silver  nitrate  solution  from  a  burette  drop 
by  drop  until  a  permanent  brownish  color  remains. 

6.  Read  the  number  of  c.  c.  of  the  silver  nitrate  solution 
used  and  determine  the  percentage  of  salt  in  the  butter. 
With  an  N/10  solution,  each  c.  c.  is  equivalent  to  one  per 
cent  of  salt,  which  gives  directly  the  percentage  of  salt  in  the 
sample. 

Data: 


Butter 

Margarine 

Cheese 

1 

2 

3 

Application:     1.     What  percentage  of  salt  does  the  aver- 
age butter  market  demand? 

2.  Is  all  butter  salted? 

3.  In  what  way  is  salt  beneficial  to  butter? 

4.  Why  is  it  necessary  to  keep  the  silver  nitrate  in  a 
brown  glass-stoppered  bottle? 

Student's  Notes: 


40  DAIRY  LABORATORY  GUIDE 

EXERCISE  16 

TESTS  FOR  RENOVATED  BUTTER  AND  MARGARINE 

Object:  To  determine  the  action  of  genuine  butter,  ren- 
ovated butter,  and  margarine,  when  heated  and  cooled. 

Apparatus :  Samples  of  genuine  butter,  renovated  butter, 
margarine;  spoon;  beaker;  and  flame. 

Steps:  1.  Spoon  Test.  Take  a  piece  of  each  sample 
about  the  size  of  a  chestnut  and  melt  it  in  a  spoon  over  a  slow 
flame.  Bring  the  fat  to  the  boiling  point  and  stir  gently 
with  a  splinter  of  wood.  The  genuine  butter  will  produce 
much  foam  and  make  little  noise  on  boiling.  The  renovated 
butter  and  the  margarine  produce  no  foam,  and  boil  with 
much  noise  and  sputtering. 

2.  Waterhouse  Test.    Put   about    100    c.   c.    of   sweet 
milk  or  water  in  the  beaker  and  then  add  a  piece  of  the 
sample  and  heat  until  it  is  melted.     Stir  with  a  splinter  of 
wood  while  heating  and  then  set  the  beaker  into  ice  cold  water 
to  cool.     On  being  stirred,  the  margarine  will  collect  in  a 
lump,  while  genuine  butter-fat  will  remain  separated  into  fine 
granules. 

3.  Mix  together  well  a  small  amount  each  of  genuine 
butter  and  beef  tallow,  and  examine  according  to  the  tests. 

4.  Mix  together  well  a  small  amount  each  of  genuine 
butter  and  lard  and  examine  according  to  the  tests. 

5.  Take  equal  parts  of  butter,  tallow,  lard,  and  cotton- 
seed oil;  then  mix  them  together  well  and  examine  accord- 
ing to  the  tests. 

Application:  1.  What  is  the  current  market  value  of 
creamery  butter?  Of  beef  tallow?  Of  lard?  Of  cottonseed 
oil? 

2.  If  butter  containing  82.5%  of  butter-fat  sells  for  25c 
per  pound,  what  should  be  the  market  price  per  pound  of 


DAIRY  LABORATORY  GUIDE  41 

butterine  containing  50%   of  foreign  fats  worth   15c  per 
pound? 

3.  If  renovated  butter  is  made  from  butter  grading 
Thirds  on  the  market  and  selling  for  15c  per  pound,  what 
should  the  renovated  butter  sell  for  per  pound? 

Student's  Notes: 


42 


DAIRY  LABORATORY  GUIDE 


Fig.  5.     The    original  Babcock  milk  tester. 
Circular  32). 


(Wisconsin 


PART  TWO 


THE  TESTING  OF  DAIRY  PRODUCTS 

The  percentage  of  butter-fat  is  made  the  basis  for  deter- 
mining the  market  value  of  nearly  all  dairy  products,  and  is 
calculated  by  the  Babcock  test.  In  connection  with  the  test 
for  butter-fat  there  are  several  other  tests  which  are  often 
used  to  determine  the  quality  and  the  composition  of  dairy 
products.  In  acquiring  a  knowledge  in  the  manipulation  of 
these  tests  the  student  will  need  to  practice  extreme  accuracy. 

Taking  Samples.  The  butter-fat  exists  in  milk  in 
minute  globules  which  float  about  in  the  milk  and  are  brought 
to  the  top  by  the  action  of  gravity.  The  milk  and  cream 
must  be  mixed  thoroughly  with  a  stirring  rod  or  by  pouring 
from  one  container  into  another  before  taking  the  sample  to 
test.  A  small  sample  dipper  or  sampling  tube  will  serve  in 
taking  the  sample. 

A  composite  sample  is  one  made  up  from  milk  delivered 
at  different  times  or  from  several  cans,  and  should  give  an 
average  test  for  the  period  or  for  the  total  amount  of  milk. 
Care  is  necessary  to  take  a  proportionate  amount  from  each 
can  in  order  to  get  a  representative  test  of  the  whole  amount. 

Preserving  Samples.  In  case  the  samples  cannot  be 
tested  immediately,  they  may  be  kept  from  souring  by  using 
chemicals.  The  preservatives  in  common  use  are  corrosive 
sublimate  and  bichromate  of  potash.  These  are  put  up  in 
convenient  tablet  form  of  sufficient  strength  that  one  or  two 


44  DAIRY  LABORATORY  GUIDE 

will  preserve  a  pint  of  milk  for  several  weeks.  The  tablets 
are  very  poisonous,  and  so  are  colored  red  and  yellow  respec- 
tively, as  a  safeguard  against  accidents. 

Churned  Milk.  It  often  happens  that  milk  will  become 
partially  churned  in  transit,  especially  if  the  container  is  not 
completely  filled,  and  the  butter-fat  will  gather  in  lumps. 
When  this  occurs  it  is  well  to  warm  the  milk  to  about  100°  F., 
and  hold  it  there  until  the  lumps  of  fat  are  melted  and  then 
mix  thoroughly  by  pouring  before  taking  the  sample  to  test. 

Frozen  Milk.  The  water  in  the  milk  or  cream  freezes 
first,  which  forces  the  solids  toward  the  center  of  the  can.  In 
order  to  get  a  representative  sample,  all  frozen  portions  must 
be  thawed  out  and  then  the  entire  contents  of  the  can  must 
be  thoroughly  mixed  before  taking  the  sample  to  test. 

Sour  Milk.  The  casein  in  milk  coagulates  on  souring  and 
tends  to  incorporate  the  fat  globules,  which  often  makes  it 
difficult  to  secure  an  accurate  sample.  In  case  the  sample 
becomes  sour,  a  small  quantity  of  alkali  added  to  the  milk 
will  dissolve  the  casein  sufficiently  to  enable  an  accurate  sam- 
ple to  be  taken.  It  is  well  to  take  a  definite  quantity  of  the 
alkali  and  in  proportion  to  the  size  of  the  milk  sample,  which 
will  enable  a  corresponding  correction  in  reading  the  test. 

How  TO  CALIBRATE  GLASSWARE 

A  great  deal  of  the  glassware  used  for  testing  has  not  been 
carefully  standardized  before  leaving  the  factory,  and  so  is 
very  unreliable.  In  order  to  insure  accuracy,  it  is  often 
necessary  for  the  operator  of  the  Babcock  test  to  calibrate 
the  glassware. 

Milk  Bottles.  1.  Plunger  Method.  This  plan  requires 
the  use  of  a  metal  plunger  made  in  two  parts  connected  with 
a  wire.  Each  part  is  of  the  proper  size  to  displace  1  c.  c.  of 


DAIRY  LABORATORY  GUIDE  45 

liquid.  In  making  the  test,  fill  the  test  bottle  to  the  zero 
mark  with  water  or  a  similar  liquid;  then  remove  with  a  strip 
of  blotting  paper  all  drops  adhering  to  the  neck  within,  and 
insert  the  plunger.  If  the  bottle  is  graduated  accurately, 
the  liquid  will  rise  from  the  zero  mark  to  the  5%  mark 
when  the  first  part  of  the  plunger  is  submerged,  and  to  the 
10%  mark  when  the  second  part  of  the  plunger  is  sub- 
merged. Any  test  bottle  showing  a  variation  of  .2  %  is  not 
sufficiently  accurate  to  insure  a  reliable  test. 

2.  Liquid  Method.  A  very  satisfactory  way  is  to  color 
some  water  with  dark  ink;  then  transfer  this  to  the  bottle  to 
be  tested  and  fill  to  the  zero  mark.  Remove  all  drops  adher- 
ing to  the  neck  within  and  add  1  c.  c.  of  the  water  from  a 
burette  or  pipette.  If  the  graduations  are  accurate,  the 
liquid  will  then  extend  to  the  5%  mark.  Add  another  cubic 
centimeter  of  the  liquid,  which  should  bring  the  surface  of  the 
liquid  to  the  10%  mark.  Any  fraction  of  the  scale  may  be 
tested  by  adding  .2  c.  c.  of  the  liquid,  which  represents  one  per 
cent  on  the  scale. 

Cream  Bottles.  The  same  methods  employed  in  testing 
milk  bottles  may  be  used  in  calibrating  cream  bottles. 

Pipettes.  The  liquid  method  can  be  used  to  advantage 
in  testing  the  pipette.  Close  the  tip  end  of  the  pipette  and 
then  add  from  a  burette  or  from  a  standardized  pipette  17.6 
c.  c.  of  the  liquid.  If  the  pipette  is  accurately  made,  the 
liquid  should  reach  to  the  mark  on  the  neck. 

How  To  CLEAN  GLASSWARE 

It  is  well  to  empty  the  test  bottles  into  an  earthen  jar 
immediately  after  completing  the  test  and  before  the  butter- 
fat  becomes  crystallized.  The  test  bottles  will  need  to  be 
shaken  while  being  emptied  to  loosen  the  lime  sediment  cling- 
ing to  the  bottom. 


46  DAIRY  LABORATORY  GUIDE 

The  glassware  used  in  testing  readily  accumulates  a  film 
of  butter-fat  and  has  to  be  kept  thoroughly  cleaned  so  as  not 
to  interfere  with  the  test.  The  fat  can  be  removed  by  wash- 
ing in  a  solution  of  water  to  which  a  small  amount  of  washing 
powder  has  been  added  and  well  dissolved  by  boiling.  A 
small  brush  will  aid  materially  in  cleaning  the  glassware,  after 
which  it  will  need  to  be  rinsed  in  clean  water  and  inverted  in 
a  rack  to  drain  and  dry. 


DAIRY  LABORATORY  GUIDE  47 


Fig.  6.      An  experiment  station  expert  making  tests  for  official  dairy  records. 


DAIRY  LABORATORY  GUIDE 


EXERCISE  1 

OPERATION  OF  THE  BABCOCK  TEST 

Object:  To  determine  the  percentage  of  butter-fat  in 
dairy  products  by  the  Babcock  method. 

Apparatus:  Samples  to  be  tested,  two  milk  bottles,  17.6 
c.  c.  pipette,  acid  measure,  beaker,  tester,  acid,  and  water. 

Steps:     1.     Number  the  test  bottles  1  and  2. 

2.  Mix  the  samples  well  by  pouring  from  one  beaker  to 
another;  then  measure  into  each  bottle  with  the  pipette  17.5 
c.  c.  of  the  milk. 

3.  Add  17.5  c.  c.  of  sulfuric  acid  to  each  bottle  and  mix 
well  by  rotary  motion  until  all  of  the  curd  is  thoroughly 
digested. 

4 .  Put  the  bottles  into 
the  tester  and  whirl  at  full 
speed  for  two  minutes.     It 
may  be  necessary  to  whirl 
longer. 

5.  Add  hot  water  to 
each  until  the  butter-fat 
rises  to  the  neck   of  the 
bottle. 

6.  Whirl  again  at  full 
speed  for  two  minutes. 

7.  Add  hot  water  until  the  butter-fat  rises  half  way  up 
the  neck  of  the  bottle;  then  whirl  one  minute  and  read 
the  test. 

8.  Always  read  each  test  carefully  and  record  all  data 
accurately  in  the  exercises  that  follow. 

Reading  the  Test.  The  whole-milk  test  is  read  from  the 
extremes  of  the  top  meniscus  to  the  bottom  of  the  fat  column, 
as  indicated  by  Nos.  1  and  2,  Fig.  8,  page  50. 


7.     Proper  method  of  filling  the  test 


"ig.   7. 
bottle. 


DAIRY  LABORATORY  GUIDE 


49 


The  cream  test  is  read  from  the  bottom  of  the  top  menis- 
cus to  the  bottom  of  the  fat  column,  as  indicated  by  Nos.  3 
and  2,  Fig.  8,  page  50. 

Data: 


Sample 

Test 

B.  F. 

Value 

Error 

Value 

1 

2 

3 

4 

Application:  1.  How  much  butter-fat  will  be  obtained 
in  one  year  from  a  cow  giving  5000  pounds  of  milk  testing  as 
above? 

2.  What  will  be  the  cash  value  of  the  butter-fat  at  cur- 
rent prices  per  pound? 

3.  What  will  be  the  loss  due  to  error  in  testing? 

4.  Why  pour  the  sample  back  and  forth  before  taking  the 
sample  to  test? 

5.  What  is  the  correct  method  of  holding  the  pipette? 

6.  Why  is  the  Babcock  test  based  upon  18  grams? 

7.  Why  use  17.6  c.  c.  of  milk  for  the  test? 

8.  Why  whirl  the  tester  at  high  speed? 

Student's  Notes: 


50  DAIRY  LABORATORY  GUIDE 

EXERCISE  2 

MIXING  MILK  AND  ACID  FOR  TESTING 

Object :    To  determine  the  effect  upon  the  reading  of  the 
test  from  incomplete  mixing  of  the  milk  and  acid. 

Apparatus :    Sample  of  milk,  four  whole-milk  test  bottles, 
and  testing  outfit. 

Steps:     1.     Number  the  bottles  from 
1  to  4. 

2.  Mix  the  sample  well  and  measure 
17.5  c.  c.  into  each  bottle. 

3.  Add  a  measure  of  acid  to  each 
bottle. 

4.  Mix  numbers  1  and  2  well  until 
all  curd  is  thoroughly  digested. 

5.  Do  not  mix  3  and  4  quite  enough 
but  leave  a  little  white  undigested  curd 
on  top. 

6.  Put  into  tester  and  proceed  with 
rig.  s.    HOW  the  fat    the  remainder  of  the  test  according  to 

column  should  be   read. 

Exercise  1. 
Data: 


Crefcto 


Thoroughly  digested 

Not  thoroughly  digested 

Sample 

1 

2 

3 

4 

Test 

B.  F. 

Value 

Error 

Application:  1.  What  will  be  the  amount  of  butter-fat 
in  one  year  from  a  cow  giving  5000  Ibs.  of  milk  testing  the 
above  percentage? 


DAIRY  LABORATORY  GUIDE  51 

2.  What  will  be  the  value  of  the  butter-fat  according  to 
your  tests  at  current  prices? 

3.  What  will  be  the  loss  on  error  in  one  year  due  to 
methods  of  mixing? 

4.  How  may  one  tell  when  the  milk  and  the  acid  are  com- 
pletely mixed? 

5.  Why  is  there  an  error  when  the  curd  is  not  thoroughly 
digested? 

6.  Why  tip  and  turn  the  bottle  when  adding  acid? 

Student's  Notes: 


52 


DAIRY  LABORATORY  GUIDE 


EXERCISE  3 

VARYING  THE  AMOUNT  OF  ACID  IN  TESTING 

Object :  To  determine  the  effect  upon  the  reading  of  the 
test  from  using  varying  amounts  of  acid. 

Apparatus :  Samples  of  whole  milk,  four  milk  test  bottles, 
small  graduate,  and  testing  outfit. 

Steps:  1.  Arrange  the  bottles  and  number  them  from 
1  to  4,  respectively. 

2.  Prepare  the  samples  of  whole  milk  for  testing  accord- 
ing to  the  previous  exercises. 

3.  Add  10  c.  c.  of  acid  to  bottle  No.  1. 

4.  Add  17.5  c.  c.  of  acid  to  bottle  No.  2. 

5.  Add  25  c.  c.  of  acid  to  bottle  No.  3. 

6.  Add  the  regular  amount  of  acid  to  bottle  No.  4. 

7.  Mix  all  the  tests  well;  then  complete  the  test  as  usual. 


Fig.  9.     The  relative  proportion  of  butter-fat  and  serum  in  dairy  products. 

These  diagrams  will  serve  to  show  the  relative  proportion 
of  butter-fat  and  serum  in  dairy  products.  The  proportion 
of  serum  decreases  as  the  butter-fat  increases;  therefore  less 
acid  is  required  when  testing  products  rich  in  butter-fat. 
Figure  No.  1  represents  skimmilk,  buttermilk,  and  whey;  No. 
2,  whole  milk;  and  No.  3,  average  cream. 


DAIRY  LABORATORY  GUIDE 


Data: 


10  c.  c. 

17.5  c.  c. 

25  c.  c. 

Check 

Sample 

1 

* 

3 

4 

Test 

B.  F. 

Value 

Error 

Application:     1.     How  much  butter-fat  would  be  ob- 
tained from  5000  Ibs.  of  milk  according  to  the  various  tests? 

2.  What  would  be  the  value  of  the  butter-fat  at  current 
prices? 

3.  How  much  would  the  error  amount  to  in  each  case? 

4.  What  is  the  cause  for  variation  in  color  of  butter-fat? 

5.  What  are  the  results  from  using  too  little  acid? 

6.  What  would  be  the  effect  of  using  weak  acid? 

7.  How  does  the  use  of  too  much  acid  affect  the  reading 
of  the  test? 

8.  How  would  the  use  of  too  strong  acid  affect  the  read- 
ing of  the  test? 

Student's  Notes: 


54 


DAIRY  LABORATORY  GUIDE 


EXERCISE  4. 

TEMPERATURE  OF  THE  WATER  IN  TESTING 

Object:  To  determine  the  influence  of  the  temperature 
of  the  added  water  upon  the  accuracy  of  the  test. 

Apparatus:  Sample  of  milk,  two  whole-milk  bottles, 
thermometer,  and  testing  outfit. 

Steps :  1.  Prepare  four  test  bottles  by  numbering;  then 
execute  the  first  four  steps  in  Exercise  1. 

2.  Add  cold  water  with  a  temperature  of  50°  F.  to  sam- 
ple No.  1. 

3.  Add  warm  water  with  a  temperature  of  100°  F.  to  sam- 
ple No.  2. 

4.  Add  hot  water  with  a  temperature  of  140°  F.  to  sam- 
ple No.  3. 

5.  Add  very  hot  water  with  a  temperature  of  180°  F. 
to  sample  No.  4. 

6.  Complete  the  test  as  usual,  noting  the  influence  of  the 
various  temperatures  of  the  water  upon  the  appearance  of 
the  fat  column  and  on  the  accuracy  of  the  test. 

Data: 


Temp.    50°    F. 

Temp.   100°  F. 

Temp.  140  °  F. 

Temp.  180°  F. 

Sample 

1 

2 

3 

4 

Test 

B.  F. 

Value 

Error 

DAIRY  LABORATORY  GUIDE  55 

Application :  1 .  How  much  butter-fat  would  you  obtain 
from  5000  Ibs.  of  milk  according  to  your  test  at  the  various 
temperatures? 

2.  What  would  be  the  value  of  the  butter-fat  at  2c  above 
current  quotations  for  New  York  Extras? 

,   3.     How  much  would  the  error  amount  to  per  year  from 
the  above  tests? 


Fig.   10.     Hand  testers. 

4.  What  temperature  of  the  sample  gives  the  best  test? 

5.  What  degree  of  temperature  of  water  gives  the  best 
test? 

6.  What  effect  has  the  cold  water  upon  the  accuracy  of 
the  reading  of  the  test? 

7.  In  what  condition  should  the  butter-fat  be  when  the 
reading  is  taken? 

8.  What  would  be  the  results  if  the  milk  were  cold? 

9.  How  would  cold  acid  affect  the  test? 

10.  How  would  hot  acid  affect  the  test? 

11.  How  could  you  get  an  accurate  test  with  an  open 
tester  if  the  test  room  were  cold? 

12.  What  is  the  object  of  a  check  test? 


56 


DAIRY  LABORATORY  GUIDE 


EXERCISE  5 

TESTING  SKIMMILK,  BUTTERMILK,  AND  WHEY 

Object:  To  determine  the  percentage  of  butter-fat  in 
skimmilk,  buttermilk,  and  whey  by  the  Babcock  method. 

Apparatus :  Samples  of  each  kind  of  product,  two  skim- 
milk  test  bottles,  and  testing  outfit. 

Steps :  Number  the  test  bottles  1  and  2  and  then  measure 
17.5  c.  c.  of  the  sample  to  be  tested  into  each  and  proceed  with 
the  test  as  usual.  The  only  difference  in  making  a  test  of 
these  products  and  that  of  the  whole  milk  is  in  using  a  double- 
neck  bottle. 

2.  Use  a  little  more  than  17.5  c.  c.  of  acid  in  testing  prod- 
ucts low  in  butter-fat. 

3.  In  case  air  bubbles  collect  in  the  neck  of  the  bottle 
when  adding  the  water,  tap  the  bottle  gently  on  the  table. 

4.  Learn  to  read  accurately,  as  the  graduations  on  the 
bottles  may  differ. 

Data: 


Skimmilk 

Buttermilk 

Whey 

Sample 

1 

2 

/ 

2 

1 

2 

Test 

Butter-fat 

Value 

Loss  on  error 

Application:  1.  How  much  butter-fat  will  be  lost  in 
4500  Ibs.  of  skimmilk  according  to  above  tests? 

2.  What  will  be  the  cash  value  of  the  butter-fat  at  cur- 
rent prices  per  lb.? 


DAIRY  LABORATORY  GUIDE  5? 

3.  Complete  the  data  for  the  same  amount  of  buttermilk 
and  of  whey. 

4.  Why  does  the  skimmilk  bottle  differ  from  the  whole 
milk  bottle? 

5.  Why  should  one  use  a  little  more  than  a  full  measure 
of  acid  when  testing  skimmilk  and  buttermilk? 

Student's  Notes: 


58 


DAIRY  LABORATORY  GUIDE 


EXERCISE  6 

TESTING  CREAM 

Object:  To  determine  the  percentage  of  butter-fat  in 
cream  by  the  Babcock  method. 

Apparatus:  Samples  of  cream,  two  cream  test  bottles, 
cream  test  scale,  and  testing  outfit. 

Steps:  1.  Prepare  the  bottles  by  numbering;  then 

balance  them  on  the  scales. 

2.  Mix  the  cream  well 
by  pouring  and  then  transfer 
18  gr.  of  the  sample  to  each 
bottle    by     means     of    the 
pipette. 

3.  Add    somewhat    less 
than  a  full  measure  of  acid  to 
each  and  proceed  with   the 
test  as  usual. 

4.  Read  the   test  care- 
fully according  to  rule  in  the 

Fig.  u.   Cream  scales.  text  and  record  all  data. 

Data: 


Sample 

1 

2 

Test 

B.  F. 

. 

Value 

Loss  on  error 

Application:     1.     Compute  the  amount  of  butter-fat  in 
750  Ibs.  of  cream  according  to  the  various  tests. 


DAIRY  LABORATORY  GUIDE  59 

2.  What  is  the  value  at  2c  above  current  quotations  for 
Extras  on  New  York  butter  market? 

3.  Compute  the  loss  in  each  case  due  to  error  in  testing. 

4.  Why  use  less  acid  in  testing  cream  than  in  the  case  of 
whole  milk  or  skimmilk? 

5.  In  testing  cream  what  should  be  the  color  of  the  fat 
column? 

6.  How  does  the  rule  for  reading  the  cream  test  differ 
from  reading  the  whole-milk  test? 

7.  What  is  centrifugal  force? 

8.  What  is  meant  by  specific  gravity? 

9.  What  is  the  Sp.  Gr.  of  whole  milk?  Skimmilk?  B.  F.? 

Student's  Notes: 


60  DAIRY  LABORATORY  GUIDE 

EXERCISE  7 

MEASURING  AND  WEIGHING  CREAM 

Object:  To  determine  the  effects  of  measuring  and 
weighing  thin  and  thick  cream  upon  the  accuracy  of  the  Bab- 
cock  test. 

Apparatus :  Samples  of  cream,  four  cream  test  bottles, 
cream  scale,  and  testing  outfit. 

Steps :     1 .     Number  the  bottles  from  1  to  4. 

2.  Mix  the  samples  well  by  pouring  them  several  times. 

3.  Weigh  18  gr.  of  thin  cream  into  bottle  No.  1  and  18 
gr.  of  thick  cream  into  bottle  No.  3. 

4.  Measure  with  the  pipette  17.5  c.  c.  of  thin  cream  into 
bottle  No.  2  and  17.5  c.  c.  of  thick  cream  into  bottle  No.  4. 

5.  Proceed  with  the  test  as  usual  for  cream;  then  read 
and  record  the  tests. 

Data: 


Thin 

Thick 

Sample 

1 

2 

3 

4 

Test 

B.  F. 

Value 

Loss  on  error 

Application:  1.  Compute  the  value  at  current  prices 
of  the  butter-fat  lost  in  one  year  from  a  cow  producing 
750  Ibs.  of  cream. 

2.  From  your  results,  which  is  the  correct  way  to  transfer 
the  cream  to  the  test  bottle?     Why? 

3.  Why  is  the  cream  sample  weighed  instead  of  measured 
into  the  test  bottle? 


DAIRY  LABORATORY  GUIDE  61 

Student's  Notes: 


62 


DAIRY  LABORATORY  GUIDE 


EXERCISE  8 

SPEED  OF  THE  BABCOCK  TESTER 

Object:  To  determine  the  effect  from  a  variation  in 
speed  of  the  tester  upon  the  percentage  reading  of  butter-fat. 

Apparatus :  Samples  of  milk,  skimmilk,  and  cream;  three 
bottles  for  each  sample  to  be  tested;  and  testing  outfit. 

Steps:  1.  Number  each  set  of  bottles  1,  2,  and  3;  then 
prepare  the  samples  by  pouring. 

2.  Measure  17.5  c.  c.  of  milk  into  each  of  the   three 
whole-milk  bottles  and  17.5  c.  c.  of  skimmilk  into  each  of 
the  skimmilk  bottles.     Then   weigh  18  gr.  of  cream  into 
each  of  the  cream  bottles. 

3.  Complete  the  test  as  usual  but  run  the  sets  at  the 
different  speeds  indicated  below. 

4.  The  testers  are  not  all  geared  alike;  so  be  sure  to  use 
the  same  tester  throughout  the  exercise;  otherwise  the  final 
results  will  be  of  no  comparative  value 

Data: 


Speed 

Half 

Full 

High 

Sample 

Milk 

S.M. 

Cream 

Milk 

S.M. 

Cream 

Milk 

S.M. 

Cream 

Test 

B.  F. 

Value 

Loss  on  error 

Application:  1  Determine  the  number  of  turns  of  the 
handle  per  minute  for  each  speed.  Likewise  compute  the 
revolutions  of  the  tester. 


DAIRY  LABORATORY  GUIDE  63 

2.  Determine  the  correct  amount  of  butter-fat  from  a 
cow  producing  5000  Ibs.  of  milk  in  one  year  according  to  the 
above  test. 

3.  Determine  from  your  tests  the  amount  of  butter-fat 
in  4250  Ibs.  of  skimmilk  and  750  Ibs.  cream.     Compute  the 
value  of  butter-fat  at  current  prices. 

4.  How  does  low  speed  of  tester  affect  the  test? 

5.  How  can  one  tell  when  the  proper  speed  of  the  tester 
is  reached? 

Student's  Notes: 


64 


DAIRY  LABORATORY  GUIDE 


EXERCISE  9 

TEMPERATURE  IN  READING  THE  TESTS 

Object :  To  determine  the  influence  of  varying  temper- 
atures upon  the  accuracy  of  the  test  in  reading  the  fat  column 
of  milk  and  cream. 

Apparatus :  Samples  of  milk  and  cream,  two  whole-milk 
bottles,  two  cream  bottles,  thermometer,  and  testing  outfit. 

Steps:  1.  Prepare  the  samples  and  complete  the  tests 
as  usual. 

2.  Read  immediately  after  stopping  the  tester  and  record 
the  temperature  by  inserting  a  thermometer  into  the  neck  of 
one  of  the  cream  bottles  until  the  mercury  bulb  is  immersed 
in  the  butter-fat.    Allow  it  to  remain  in  place  throughout  the 
exercise  and  use  this  reading  for  all  of  the  other  bottles. 

3.  Reread  the  tests  at  intervals  of  three  and  five  minutes 
when  left  standing. 

4.  Set  the  test  bottles  into  a  waterbath  at  120°F.  for 
two  minutes;  then  reread  and  record  all  data. 

5.  Set  the  test  bottles  into  a  waterbath  at  70°F.  for 
two  minutes;  reread. 

Data: 


Milk 

Vari- 
ation 

Cream 

Vari- 
ation 

Temp. 

Samples 

1 

2 

/ 

I 

Read  immediately 

Read  after  2  min. 

Read  after  5  min. 

Read  at  120  °F. 

Read  at   70  °F. 

DAIRY  LABORATORY  GUIDE  65 

Application :     1 .        Is  there  any  difference  in  the  appear- 
ance of  the  fat  column  after  standing;  if  so,  what  is  the  cause? 

2.  How  are  the  readings  affected  by  standing? 

3.  What  temperature   of  the  butter-fat  column  gives 
the  correct  reading  of  the  test?    Why? 

4.  How  may  the  test  bottles  be  kept  warm  when  whirl- 
ing in  a  hand  tester? 

5.  How  may  the  test  bottles  be  kept  warm  when  reading 
in  cold  surroundings? 

Student's  Notes: 


66  DAIRY  LABORATORY  GUIDE 

EXERCISE  10 

TESTING  CHEESE 

Object:  To  determine  the  butter-fat  content  of  cheese 
by  the  Babcock  method. 

Apparatus:  Samples  of  Cheddar,  Cream,  Club,  and 
Swiss  cheese;  four  50%  cream  test  bottles;  and  testing  outfit. 

Steps:  1.  Prepare  the  samples  of  cheese  by  pulver- 
izing very  fine  with  a  knife. 

2.  Balance  the  bottles  on  the  scales;  then  weigh  into 
each  4^  grams  of  the  prepared  sample. 

3.  Add  gradually  to  each  bottle  about  10  c.  c.  of  hot 
water  and  shake  in  the  meantime  until  all  of  the  curd  is 
thoroughly  dissolved.     To  hasten  disintegration,  add  a  few 
c.  c.  of  sulfuric  acid. 

4.  After  the  curd  is  thoroughly  disintegrated,  add  about 
10  c.  c.  of  acid  to  each  sample  to  digest  the  curd;  then  com- 
plete the  test  as  with  cream. 

Rule  1 .  In  order  to  obtain  the  correct  percentage  of  but- 
ter-fat, increase  the  reading  by  whatever  factor  the  sample  is 
of  18  grams. 

Rule  2.  Multiply  the  reading  by  18  and  divide  by  the 
number  of  grams  in  the  sample  tested. 

Data: 


Sample 

Cheddar 

Cream 

Club 

Swiss 

Test  reading 

Corrected  test 

Application:  1.  Why  is  it  necessary  to  pulverize  the 
cheese  well  when  preparing  the  sample? 

2.  Why  is  it  well  to  disintegrate  the  curd  with  hot  water 
before  adding  the  acid? 


DAIRY  LABORATORY  GUIDE  67 

3.  Why  use  less  than  18  grams  of  the  sample  in  testing 
cheese? 

4.  How  much  butter-fat  does  the  full  cream  cheese  con- 
tain?    Half  cream? 

5.  How  does  Cheddar  cheese  compare  with  cream  cheese 
in  fat  content?    What  is  a  filled  cheese? 

6.  How  does  Club  cheese  compare  with  full  cream  cheese 
in  fat  content? 

Student's  Notes: 


68  DAIRY  LABORATORY  GUIDE 

EXERCISE  11 

DETERMINING  THE  BUTTER-FAT  IN  BUTTER 

Object:  To  determine  the  percentage  of  butter-fat  in 
butter  according  to  the  Babcock  method. 

Apparatus:  Samples  of  butter,  two  butter  test  bottles 
or  two  cream  bottles. 

Steps:  1.  Balance  the  bottles  on  the  scales  the  same 
as  in  testing  cream. 

2.  Place  several  ounces  of  butter  in  a  beaker  and  soften 
to  the  C9nsistency  of  cream  by  heating  in  a  waterbath. 

3.  Mix  the  sample  thoroughly  and  transfer  9  grams  to  a 
butter  test  bottle  by  means  of  a  pipette. 

4.  Heat  the  sample  gently  until  it  runs  into  the  test 
bottle,  and  wash  down  all  of  the  fat  adhering  to  the  sides  of 
the  bottle  by  using  9  grams  of  hot  water. 

5.  Next  add  from  5  to  8  c.  c.  of  sulfuric  acid  and  com- 
plete the  test  as  with  cream. 

6.  In  case  butter  test  bottles  are  not  at  hand,  the  test 
may  be  made  by  using  cream  bottles.     Weigh  out  4^  grams 
of  the  butter  sample  into  the  cream  bottle ;  then  add  the  same 
amount  of  hot  water  and  shake  well.     Add  about  5  c.  c.  of 
sulfuric  acid  and  complete  the  test  as  with  cream. 

7.  To  correct  the  readings  of  the  test,  use  the  same  rule 
as  in  testing  cheese. 

8.  Care  will  be  necessary  not  to  burn  the  butter-fat  by 
an  excessive  amount  of  acid. 

Data: 


Sample 

i 

3 

3 

4 

Test  reading 

Corrected  test 

DAIRY  LABORATORY  GUIDE  69 

Application:     1.     What  is  the  standard  percentage  of 
butter-fat  in  butter? 

2.  What  is  whey  butter? 

3.  What  is  the  object  of  melting  the  butter  and  thor- 
oughly mixing  before  taking  the  sample? 

4.  In  what  other  way  may  the  butter-fat  content  of 
butter  be  determined? 

5.  Of  what  value  is  such  a  test  to  the  buttermaker? 

Student's  Notes: 


70 


DAIRY  LABORATORY  GUIDE 


EXERCISE  12 

TESTING  CONDENSED  MILK 

Object:  To  determine  the  percentage  of  butter-fat  in 
condensed  milk,  containing  no  added  sugar. 

Apparatus :  Sample  of  unsweetened  condensed  milk,  four 
milk  bottles,  50  c.  c.  graduate,  and  testing  outfit. 

WEIGHT  METHOD 

Steps:     1.     Number  bottles  1  to  4. 

2.  Balance  bottles  1  and  2  on  the  cream  scales;  then 
weigh  into  each  9  grams  of  the  sample. 

3.  Add  9  grams  of  water  to  each  bottle  and  dissolve  the 
sample  as  much  as  possible  before  adding  the  acid. 

Add  about  10  c.  c.  of  acid  to  the  sample;  then  complete  the 
test  as  usual  and  record  the  reading. 

VOLUME  METHOD 

Steps:  1.  Measure  into  the  graduate  20  c.  c.  of  the 
sample;  then  add  to  this  the  same  amount  of  water.  Shake 
well  until  the  milk  and  water  are  thoroughly  mixed. 

2.  Measure  17.5  c.  c.  of  the  mixture  into  bottles  No.  3 
and  4;  then  complete  the  test  as  described  under  the  previous 
method. 

3.  Record  and  correct  all  data  according  to  the  previous 
rule. 

Data: 


Weight  method 

Volume  method 

Sample 

1 

2 

3 

4 

Test  reading 

Corrected  test 

DAIRY  LABORATORY  GUIDE  71 

Application:     1.     What  is  the  object  of  adding  water  to 
the  condensed  milk? 

2.  Why  is  it  necessary  to  dissolve  thoroughly  the  con- 
densed milk  before  taking  the  sample? 

3.  Why  is  it  necessary  to  double  the  reading  on  complet- 
ing the  test? 

4.  How  much  is  the  volume  of  the  milk  reduced  by  the 
process  of  condensing? 

5.  What  is  evaporated  milk  and  cream? 

6.  Why  cannot  sweetened  condensed  milk  be  tested  by 
this  process? 

Student's  Notes: 


72  DAIRY  LABORATORY  GUIDE 

EXERCISE  13 

THE  SPECIFIC  GRAVITY  OF  MILK 

Object:  To  determine  the  specific  gravity  of  milk  by 
means  of  the  Quevenne  lactometer. 

Apparatus:  Samples  to  be  tested,  eight-inch  cylinder, 
thermometer,  Quevenne  lactometer,  and  Babcock  testing 
outfit. 

Steps:  1.  Test  the  sample  for  butter-fat;  then  fill  the 
cylinder  nearly  full  of  the  sample  to  be  tested. 

2.  Take  the  temperature  of  the  sample,  and  record. 

3.  Float  the  lactometer  in  the  sample  and  observe  the 
exact  point  on  the  scale  where  it  cuts  the  surface  of  the  liquid, 
and  record  the  reading.     Care  is  necessary  in  putting  the  lac- 
tometer into  the  milk  not  to  let  it  drop  to  the  bottom  of  the 
cylinder,  as  it  is  very  easily  broken. 

4.  The  scale  of  the  Quevenne  lactometer  is  divided  into 
25  equal  parts,  ranging  from  15  to  40.     Each  division  is  called 
a  degree,  and  is  divided  into  fifths.     If  the  instrument  floats 
at  18,  for  example,  it  indicates  a  liquid  whose  specific  gravity 
is  1.018. 

5.  Corrections    for    temperature:    The    lactometer    is 
standardized  at  60°  F.;  so  corrections  need  to  be  made  in 
reading  if  the  temperature  of  the  sample  varies  from  60°  F. 
For  each  degree  above  60°  add  one-tenth  to  the  lactometer 
reading;  for  each  degree  below  60°  subtract  one-tenth  from 
the  lactometer  reading.     It  is  a  good  plan  to  bring  the  tem- 
perature of  the  sample  within  the  extremes  of  50°  and  70°F., 
as  the  rules  are  only  approximately  correct. 


DAIRY  LABORATORY  GUIDE 


73 


6.  Calculate  the  solids  not  fat  (S.  N.  F.)  and  total  solids 
(T.  S.)  by  the  following  formulas.     The  total  solids  include 
the  solids  not  fat  plus  the  B.  F. 

S.  N.  F.   =   J£L  +     .2f 

T.  S.         =   ML  +  1.2f 

in  which  L  is  the  lac.  reading  at  60°  F.,  and  /  the  percentage  of  fat 
in  the  sample. 

7.  Calculate  the  percentage  of  adulteration. 

Formula : 

S.N.F.  X  100 

100-  — =  percentage  of  adulteration. 

9 

Data: 


Sample 

Temp. 

Lac. 

Correct 

Per    cent 
B.  F. 

S.  N.  F. 

T.   S. 

Per  cent 
adult. 

1 

2 

3 

4 

Application:  1.  What  is  the  Sp.  Gr.  of  normal  cow's 
milk?  Why  is  it  necessary  to  make  a  correction  in  the  lac- 
tometer reading  when  the  temperature  varies?  What  is  the 
effect  of  heating  upon  the  Sp.  Gr.  of  the  sample?  Of  cooling? 

2.  What  are  the  solids  not  fat  in  milk?     Total  solids? 

3.  What  is  the  legal  standard  for  each  in  the  United 
States? 

4.  A  sample  of  4%  milk  at  60°  F.  shows  a  lactometer 
reading  of  31.     What  is  the  percentage  of  S.  N.  F.  in  the 
sample?     Calculate  the  percentage  of  adulteration. 

5.  Find  the  S.  N.  F.  in  a  sample  of  3.5%  milk  at  28° F., 
when  the  lactometer  is  34. 

6.  If  milk  has  a  Sp.  Gr.  of  1.032  at  60°  F.,  what  will  be 
the  Sp.  Gr.  at  70°  F.?    At  50°  F.? 


74  DAIRY  LABORATORY  GUIDE 

Student's  Notes: 


PART  THREE 


THE  MANUFACTURING  OF  DAIRY  PRODUCTS 

HAND  SEPARATORS 

The  hand  separator  is  a  machine  of  unusually  high  speed. 
As  a  rule  few  operators  are  familiar  with  high-speed  machin- 
ery, and  many  times  a  separator  is  permanently  injured  before 
the  operator  learns  how  to  make  it  do  efficient  work.  The 
fact  that  the  separator  is  a  high-speed  machine  makes  it  all 
the  more  necessary  that  the  operator  realize  that  a  slight 
variation  in  the  speed,  a  small  change  in  the  cream  screw,  or 
a  few  degrees  difference  in  the  temperature  of  the  milk  will 
result  in  a  considerable  error  in  efficiency  unless  exceeding 
care  is  practiced. 

Setting.  It  is  very  necessary  in  setting  the  machine 
to  have  it  placed  upon  a  solid  foundation  of  cement  or  heavy 
timbers,  so  that  it  will  sit  level  and  run  free  from  any  vibra- 
tion. To  level  the  machine,  place  a  spirit  level  upon  the 
bowl  casing  and  then  tighten  the  lag  screws  until  the  machine 
is  level. 

Lubricating.  A  failure  to  lubricate  a  high-speed  machine 
may  result  in  cutting  out  the  bearings  in  a  very  short  time. 
At  the  present  time  many  machines  are  made  with  an  oil 
bath  within  the  frame,  which  eliminates  the  necessity  of  oil- 
ing each  bearing  separately.  It  is  usually  necessary  even 
with  this  device  to  lubricate  the  bowl  spindle  separately,  as 
that  is  the  part  most  likely  to  be  injured. 

Cleaning.  In  using  the  hand  separator,  perfect  cleanli- 
ness is  absolutely  essential  at  all  times.  A  dirty  machine  will 


76  DAIRY  LABORATORY  GUIDE 

contaminate  the  cream  and  materially  lower  the  grade.  The 
separator  bowl  needs  to  be  very  carefully  taken  apart  and  the 
contrivances  Within  handled  in  such  a  manner  that  they  will 
not  become  bent,  injured,  nor  misplaced.  All  parts  of  the 
machine  coming  in  contact  with  the  milk  need  to  be  cleaned 
each  time  after  using.  Care  is  necessary  to  first  dip  the  parts 
into  warm  water  and  clean  with  a  brush,  after  which  hot 
water  or  live  steam  will  serve  to  sterilize  them.  After  wash- 
ing, it  is  well  to  place  the  parts  in  warm  surroundings  to  drain 
and  dry  to  prevent  rusting. 


DAIRY  LABORATORY  GUIDE 


77 


.0 

G 


78  DAIRY  LABORATORY  GUIDE 

EXERCISE  1 

EXAMINATION  OF  HAND  SEPARATORS 

Object:  To  set  a  hand  separator,  knock  down  movable 
parts,  analyze  and  become  familiar  with  the  variation  in 
mechanism,  and  reassemble  ready  for  use. 

Apparatus:  A  number  of  hand  separators,  tools  accom- 
panying the  same,  level,  lag  screws,  and  copy  of  Dairy  Lab- 
oratory Guide. 

Steps:  1.  Set  the  machine  upon  a  solid  foundation  and 
then  level  the  bowl  frame  and  bolt  down  with  lag  screws. 

2.  Remove  parts  of  the  separator  sufficiently  to  enable 
a  thorough  examination  of  the  gearing;  then  locate  all  of  the 
bearings  and  oil  cups. 

3.  Take  the  bowl  apart  and  study  the  mechanism  of  the 
contrivances  within.      Locate    the    intake  and    trace  the 
course  of  the  cream  and  the  skimmilk  through  the  bowl  and 
locate  the  exits  for  each. 

4.  Trace  the  power  from  the  handle  to  the  bowl  and  note 
the  method  of  increasing  the  speed. 

5.  Determine  the  number  of  revolutions  of  the  bowl  for 
each  turn  of  the  handle;  then  determine  the  normal  speed  of 
the  bowl  per  minute. 

6.  Observe  carefully  the  manner  of  adjusting  the  height 
of  the  bowl  and  adjust  it  with  reference  to  the  cream  and 
skimmilk  pans. 

7.  In  all  of  the  subsequent  separator  exercises  be  sure  to 
clean  thoroughly  all  parts  of  the  machine  coming  in  contact 
with  the  milk;  then  wipe  the  frame  with  a  dry  cloth  each  time 
after  using. 

Application:     1.     Why  does  the  bowl  need  to  be  level? 
2.     What  is  the  object  of  the  contrivances  in  the  bowl? 


DAIRY  LABORATORY  GUIDE 


79 


3.  How  does  the  bowl  need  to  be  adjusted  with  reference 
to  the  cream  and  skimmilk  pans?    Why? 

4.  How  does  the  size  of  the  cream  and  the  skimmilk  exit 
compare  in  size?    In  position?    Why? 

5.  In  what  way  would  rusting  affect  the  separator  bowl? 
How  can  one  prevent  rusting  of  the  bowl  and  the  parts? 

6.  What  is  the  rubber  ring  for  in  the  bowl?    What  pre- 
caution is  necessary  in  washing  and  drying  the  rubber  ring? 

Data: 


Separator 

Kind  of 
bowl  bearings 

No.  oil 
bearings 

Contriv- 
ances in  bowl 

Speed  of 
handle 

Speed  of 
bowl 

Student's  Notes: 


80  DAIRY  LABORATORY  GUIDE 

EXERCISE  2 

FLUSHING  THE  SEPARATOR 

Object:  To  determine  the  loss  of  butter-fat  from  not 
flushing  the  separator  bowl  after  skimming. 

Apparatus:  Separator,  milk,  scales,  containers,  sample 
bottles,  thermometer,  and  testing  outfit. 

Steps :  1 .  Assemble  the  separator  ready  for  use.  Tem- 
per the  milk  to  85°  F.  and  weigh  out  two  lots  of  a  definite 
amount  each.  Retain  a  sample  of  whole  milk  to  test. 

2.  Separate  lot  No.  1;  then  flush  the  machine  with  one 
quart  of  warm  water  or  skimmilk.     Determine  the  weight  of 
the  cream  and  the  skimmilk  separately;  retain  samples  to 
test. 

3.  Drain  the  separator  bowl  and  separate  lot  No.  2 
without  flushing.     Determine  the  weight  of  the  cream  and 
the  skimmilk;  retain  samples  and  determine  the  percent- 
age of  butter-fat. 

4.  In  all  subsequent  hand  separator  exercises  retain  all 
skimmilk  testing  over  .02%  and  reseparate  to  avoid  unneces- 
sary waste  of  butter-fat. 

5.  After  making  the  butter-fat  tests,  record  all  of  the 
data;  then  check  your  results  and  account  for  all  of  the  butter- 
fat  in  the  original  amount  of  milk. 

Application :  1 .  Compute  the  amount  of  butter-fat  from 
a  cow  giving  annually  4000  Ibs.  of  milk  testing  4.2%,  with  a 
loss  in  the  skimmilk  as  with  the  flushed  bowl.  What  would 
be  the  value  of  the  butter-fat  at  2c  above  the  current  price 
paid  for  New  York  Extras? 

2.  What  will  the  loss  in  the  skimmilk  amount  to  in  a  year 
from  a  herd  of  five  cows  averaging  4500  Ibs.  of  milk  each? 

3.  Is  it  advisable  to  flush  the  separator  after  using?     If 
so,  flush  the  bowl  whenever  skimming. 


DAIRY  LABORATORY  GUIDE 


81 


Data: 


Flushed 

Not  flushed 

Wt. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Milk 

Cream 

Skimmilk 

Loss 

Value 

Student's  Notes: 


82 


DAIRY  LABORATORY  GUIDE 


EXERCISE  3 

WASHING  THE  SEPARATOR 

Object:  To  determine  the  effect  upon  the  efficiency  of 
the  hand  separator  from  not  washing  the  bowl  each  time 
after  using. 

Apparatus:  Separator,  milk,  containers,  scale,  sample 
bottles,  thermometer,  and  testing  outfit. 

Steps :  1.  Assemble  the  separator  ready  for  use,  temper 
the  milk  to  85°  F.,  and  weigh  out  two  lots  of  a  definite  amount 
each.  It  is  a  good  plan  to  try  this  exercise  with  several  dif- 
ferent separators,  as  the  comparative  results  will  be  of  much 
more  value. 

2.  Separate  lot  No.  1  in  a  machine  which  has  been  left 
over  night  unwashed.     Determine  the  weight  of  the  cream 
and  of  the  skimmilk  and  retain  samples  of  each  to  test. 

3.  Wash  the  separator  parts  thoroughly ;  then  reassemble 
and  skim  lot  No.  2.     Determine  the  weight  of  the  cream  and 
of  the  skimmilk  and  retain  samples  of  each  to  test.. 

4.  Test  all  of  the  samples,  make  the  computations,  and 
record  the  data. 

Data: 


Unwashed 

Washed 

Wt. 

Test 

B.F. 

Wt.' 

Test 

B.  F. 

Milk 

Cream 

Skimmilk 

Loss 

Value 

DAIRY  LABORATORY  GUIDE  83 

Application:  1.  Compute  the  loss  of  butter-fat  in  the 
skimmilk  for  one  year  from  a  cow  giving  5000  Ibs.  of  3.5% 
milk,  using  the  above  tests  for  cream  and  skimmilk. 

2.  How  much  will  the  loss  amount  to  in  a  year  at  cur- 
rent prices  for  butter-fat  in  case  the  separator  were  washed 
but  once  a  day.? 

3.  What  is  the  proper  way  to  care  for  the  separator  parts 
after  washing? 

Student's  Notes: 


84 


DAIRY  LABORATORY  GUIDE 


EXERCISE  4 

TEMPERATURE  OF  THE  MILK  FOR  SEPARATION 

Object:  To  determine  the  effects  of  variation  in  skim- 
ming temperature  upon  the  efficiency  of  the  hand  separator. 

Apparatus:  Separator,  milk,  containers,  sample  bottles, 
scale,  thermometer,  and  testing  outfit. 

Steps:  1.  Assemble  the  separator,  temper  the  milk  to 
85°  F.,  and  weigh  out  three  lots  of  a  definite  amount  each. 

2.  Temper  lot  No.  1  to  70°  F.,  lot  No.  2  to  85°  F.,  and  lot 
No.  3  to  100°  F. 

3.  Separate  each  lot  at  the  proper  speed;  then  determine 
the  weight  of  the  cream  and  the  skimmilk  and  retain  samples 
of  each  to  test. 

4.  Test  the  samples,  make  all  computations,  and  record 
the  data. 

Data: 


Temp.  70  °F. 

Temp.  85°F. 

Temp.  100  °F. 

Wt. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Milk 

Cream 

Skimmilk 

Loss 

Value 

Application:  1.  What  effect  has  the  skimming  temper- 
ature upon  the  percentage  of  butter-fat  in  the  cream? 

2.  How  does  the  temperature  affect  the  loss  of  butter-fat 
in  the  skimmilk? 


DAIRY  LABORATORY  GUIDE  85 

3.  Compute  the  loss  of  butter-fat  in  one  year  from  a  cow 
giving  4000  Ibs.  of  4%  milk,  at  current  prices  for  butter-fat. 

4.  How  does  the  separation  of  cold  milk  affect  the 
machine  mechanically?     Why? 

Student's  Notes: 


86 


DAIRY  LABORATORY  GUIDE 


EXERCISE  5 

SPEED  OF  THE  SEPARATOR 

Object:  To  determine  the  effects  of  variation  in  speed 
upon  the  efficiency  of  the  hand  separator. 

Apparatus:  Separator,  milk,  containers,  sample  bottles, 
scale,  thermometer,  and  testing  outfit. 

Steps:  1.  Assemble  the  separator,  temper  the  milk  to 
85°  F.,  and  weigh  out  three  lots  of  a  definite  amount  each. 

2.  Separate  lot  No.  1  at  proper  speed,  which  is  usually 
indicated  on  the  handle  of  the  machine.     Determine  the 
weight  of  the  cream  and  of  the  skimmilk  and  retain  samples 
of  each  to  test. 

3.  Separate  lot  No.  2  at  five  revolutions  of  the  handle 
below  proper  speed.     Determine  the  weight  of  the  cream  and 
of  the  skimmilk  and  retain  samples  to  test. 

4.  Separate  lot  No.  3  at  five  revolutions  of  the  handle 
above  proper  speed.     Determine  the  weight  of  the  cream  and 
of  the  skimmilk  and  retain  samples  to  test. 

5.  In  case  the  speed  of  the  machine  is  not  indicated  on 
the  handle,  refer  to  the  book  of  instructions  usually  accom- 
panying the  machines.     Exceeding  care  is  necessary  to  avoid 
accidents. 

Data: 


Low  speed 

Proper  speed 

High  speed 

Wt. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Milk 

Cream 

Skimmilk 

Loss 

Value 

DAIRY  LABORATORY  GUIDE  87 

Application:     1.     How  did  the  variation  in  speed  influ- 
ence the  test  of  the  cream?     The  skimmilk? 

2.  How  high  a  speed  is  necessary  to  give  efficient  skim- 
ming? 

3.  How  may  one  determine  when  the  proper  speed  is 
reached? 

Student's  Notes: 


88  DAIRY  LABORATORY  GUIDE 

EXERCISE  6 

CHANGING  THE  CREAM  SCREW  ON  THE  SEPARATOR 

Object:  To  determine  the  effect  of  adjusting  the  screw 
upon  the  variation  in  percentage  of  butter-fat  in  the  cream 
and  in  the  skimmilk. 

Apparatus:  Separator,  milk,  containers,  scale,  sample 
bottles,  thermometer,  and  testing  outfit. 

Steps:  1.  Assemble  the  separator,  temper  the  milk  to 
85°  F.,  and  weigh  out  three  lots  of  a  definite  amount  each. 

2.  Separate  lot  No.    1   with  the   screw  in   a    normal 
position;  then  determine  the  weight  of  the  cream  and  the 
skimmilk  and  retain  samples  to  test. 

3.  Adjust  the  screw  slightly  so  as  to  increase  the  per- 
centage of  butter-fat  in  the  cream  5%  above  normal.     Sepa- 
rate lot  No.  2,  determine  the  weight  of  the  cream  and  the 
skimmilk,  and  retain  samples  to  test. 

4.  Adjust  the  screw  so  as  to  decrease  the  percentage 
of  butter-fat  in  the   cream  5%   below  normal.     Separate 
lot  No.  3,  determine  the  weight  of  the  cream  and  the  skim- 
milk, and  retain  samples  to  test. 

5.  In  this  exercise  care  will  be  necessary  to  note  whether 
the  adjustment  is  done  by  means  of  a  cream  screw  or  a  skim- 
milk screw.     The  amount  of  adjustment  will  be  determined 
by  the  position  and  character  of  the  screw. 

Application:  1.  Compute  the  amount  and  the  value  at 
current  prices  of  the  butter-fat  lost  in  one  year  in  10,000  Ibs. 
of  skimmilk  when  the  percentage  of  loss  is  normal. 

2.  How  do  the  screws  in  different  makes  of  separators 
compare  as  to  the  amount  of  adjustment  required  to  obtain 
the  same  results? 

3.  In  skimming,  what  percentage  of  cream  does  the  sep- 
arator in  hand  do  the  most  efficient  work? 


DAIRY  LABORATORY  GUIDE 


89 


Data: 


Normal 

Increased  5% 

Decreased  5% 

WL 

Test 

B.F. 

Wi. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Milk 

Cream 

Skimmilk 







Loss 

Value 

Student's  Notes: 


90  DAIRY  LABORATORY  GUIDE 

EXERCISER 

COMPARISON  OF  VARIOUS  METHODS  OF  CREAMING 

Object:  To  determine  the  amount  of  butter-fat  lost 
in  skimmilk  by  various  methods  of  creaming. 

Apparatus :  Separator,  shotgun  cans,  shallow  pans,  milk 
scales,  thermometer,  and  testing  outfit. 

Steps :  1 .  Temper  a  quantity  of  milk  to  85°F.  and  weigh 
out  three  lots  of  definite  amounts. 

2.  Skim  lot  No.  1  with  a  hand  separator;  then  determine 
the  weight  of  the  cream  and  of  the  skimmilk  and  retain  sam- 
ples to  test. 

3.  Put  lot  No.  2  into   shotgun   cans  and  set  into  cold 
water  several  hours  before  creaming.     Remove  the  cream 
as  well  as  possible  by  means  of  a  perforated  skimmer;  then 
determine  the  weight  of  the  cream  and  of  the  skimmilk 
and  retain  samples  to  test. 

4.  Put  lot  No.  3  into  shallow  pans  and  set  aside  to  cool 
for  several  hours  before  creaming.     Remove  the  cream  with 
a  perforated  skimmer;  then  determine  the  weight  of  the 
cream  and  the  skimmilk  and  retain  samples  to  test. 

5.  Have  all  of  the  conditions  for  the  various  methods  as 
nearly  as  possible  like  those  found  in  practice  on  dairy  farms. 

Application:  1.  Compute  the  loss  of  butter-fat  in  the 
skimmilk  from  the  different  methods  of  creaming  from  a  herd 
of  five  cows  for  ten  months,  each  cow  averaging  500  Ibs.  of  4% 
milk  per  month. 

2.  What  are  the  advantages  of  the  deep-setting  system 
over  the  centrifugal?     The  disadvantages? 

3.  What  is  the  difference  between  the  two  gravity  sys- 
tems?   Why? 

4.  Which  system  is  the  most  practical  for  the  modern 
dairyman?    Why? 


DAIRY  LABORATORY  GUIDE 


91 


Data: 


Separator 

Deep  setting 

Shallow  pan 

WL 

Test 

B.F. 

Wt. 

Test 

B.F. 

Wt. 

Test 

B.F. 

Milk 



E 

Cream 

Skimmilk 



Loss 

Value 

Student's  Notes: 


92  DAIRY  LABORATORY  GUIDE 

BUTTER  MAKING 

The  beginner,  when  starting  a  new  line  of  work,  often 
loses  much  valuable  time  because  of  vague  notions  as  to  the 
plan  of  procedure.  The  first  thing  is  to  have  a  clear  under- 
standing of  the  object  of  the  exercise;  then  proceed  systemati- 
cally. 

Ripening.  The  cream  for  churning  needs  to  be  ripened 
until  a  definite  percentage  of  lactic  acid  is  developed.  This 
is  best  done  by  placing  the  cream  in  a  can  or  a  small  vat 
where  it  can  be  held  at  a  constant  temperature. 

The  best  temperature  for  ripening  cream  is  about  70°F. 
At  this  temperature  the  lactic  acid  bacteria  multiply  rapidly 
and  will  require  only  a  few  hours  to  sour  the  cream  so  it  is 
ready  to  churn.  It  is  well  to  stir  the  cream  frequently  during 
ripening,  in  order  that  the  acid  may  develop  evenly  and  the 
cream  be  free  from  lumps  when  put  into  the  churn. 

Preparing  the  Churn.  It  is  well  to  prepare  the  churn  by 
scalding  with  hot  water  or  steam  to  fill  up  the  openings  in  the 
wood,  destroy  germs,  and  prevent  the  lodging  of  the  butter- 
milk. After  scalding,  cool  the  churn  with  cold  water  before 
adding  the  cream. 

Lock  the  churn  so  it  will  not  revolve;  otherwise  accidents 
may  occur  and  the  cream  be  lost. 

Filling  the  Churn.  Weigh  out  a  definite  quantity  of  cream 
as  directed  in  the  exercises;  then  determine  the  percentage 
of  butter-fat  and  the  amount  of  acidity. 

Temper  the  cream  to  the  proper  degree  and  transfer  to  the 
churn.  Care  is  necessary  to  strain  the  cream  into  the  churn, 
in  order  to  eliminate  lumps  or  foreign  matter  that  may  be  in 
the  cream. 

Add  sufficient  coloring  to  bring  the  butter  to  "  June  color." 
The  amount  will  depend  upon  the  season  of  the  year.  In 


DAIRY  LABORATORY  GUIDE  93 

case  one  neglects  to  add  coloring  to  the  cream,  it  may  be  put 
in  at  the  time  of  working  by  mixing  it  well  with  the  salt. 

Agitating.  To  get  the  maximum  concussion  during  the 
agitation,  fill  the  churn  not  more  than  half  full  of  cream; 
otherwise  difficulties  may  arise. 

It  is  well  to  remove  the  air  from  the  churn  occasionally 
during  the  first  few  minutes  of  churning. 

When  to  Stop  Churning.  It  is  well  to  continue  churning 
until  the  butter-fat  granules  are  about  the  size  of  barley  ker- 
nels. This  condition  will  allow  a  more  thorough  removal  of 
the  buttermilk  with  the  wash  water.  Overchurning  gathers 
the  butter  into  larger  lumps,  incorporates  much  buttermilk, 
prevents  thorough  washing,  and  injures  the  texture  of  the 
butter. 

A  few  common  rules  in  use  are :  1.  Stop  churning  when 
the  butter  granules  are  the  size  of  barley  kernels. 

2.  Stop  churning  when  the  butter  floats  half  way  out  of 
the  buttermilk. 

3.  Stop  churning  when  the  glass  in  the  churn  cover  clears 
and  show  bubbles  of  froth. 

Washing  the  Butter.  The  wash  water  will  need  to  be 
tempered  according  to  the  directions  in  the  subsequent  exer- 
cises. Add  an  amount  of  wash  water  equal  to  that  of  the 
buttermilk;  then  turn  the  churn  a  few  revolutions  and  drain 
the  butter.  In  case  the  wash  water  is  very  milky,  wash  the 
butter  a  second  time  It  is  important  to  have  clean  water, 
free  from  odors  or  foreign  particles. 

Salting  and  Working.  The  butter  worker  is  prepared  in 
the  same  manner  as  the  churn,  after  which  the  butter  is 
removed  from  the  churn  to  the  worker  and  spread  out  evenly. 

The  markets  call  for  about  2J^%  of  salt,  which  will  require 
the  addition  of  about  one  ounce  of  salt  per  pound  of  butter-fat 
in  the  cream,  The  salt  will  need  to  be  sprinkled  evenly  over 


94 


DAIRY  LABORATORY  GUIDE 


13.     A  butter-worker. 


the  butter  and  then  worked  in  thoroughly.  To  prevent  over- 
working, it  may  be  well  to  let  the  butter  stand  for  a  few  min- 
utes in  order  to  let  the  salt  dissolve,  and  then  rework. 

It  is  extremely  easy  to  overwork  the  butter,  especially 
small  quantities,  and  the  student  will  do  well  to  take  much 
precaution  at  this  point. 
Overworking  destroys 
the  grain  and  makes  the 
butter  gummy,  smeary, 
or  salvy  in  texture. 

Packing.  The  best 
way  to  pack  butter  is  in 
thoroughly  sterilized 
stone  jars  or  in  pound 
prints.  Butter  packs  the 
best  when  taken  directly 
from  the  worker,  but  the 
prints  can  be  made  cleaner  cut  and  more  attractive  by  allow- 
ing the  fresh  butter  to  sit  in  a  cool  place  for  a  few  hours. 

The  Overrun.  Overrun  means  merely  that  one  pound  of 
butter-fat,  when  made  into  butter,  will  produce  more  than 
a  pound  of  butter,  just  the  same  as  a  pound  of  flour,  when 
mixed  with  water,  milk,  yeast,  and  salt,  will  make  more  than 
a  pound  of  bread — or  will  over-run. 

During  the  process  of  churning,  the  butter-fat  is  brought 
together  by  agitation;  then  the  butter-fat  is  washed  to  remove 
as  much  of  the  remaining  milk  as  possible  and  then  salted  and 
worked. 

Average  butter  is  composed  of  the  following  substances: 

Butter-fat 82.5  per  cent 

Water 14.0  per  cent 

Casein  (curd) 1.0  per  cent 

Mineral  matter  (salt,  etc.) 2.5  per  cent 

Total 100.0  per  cent 


DAIRY  LABORATORY  GUIDE 


95 


Not  all  butter  analyzes  the  same.  The  proportions  of  the 
several  constituents  vary,  depending  upon  the  condition  of 
the  fat,  the  efficiency  of  the  apparatus  used,  and  the  skill  of 
the  maker.  The  water,  of  course,  varies  the  most.  Water 
in  butter,  however,  must  not  exceed  16%. 


/  Pound 


gutter 


Fig.   14.     A  graphic  explanation  of  overrun. 

A  hundred  pounds  of  30%  cream  contains  30  Ibs.  of 
butter-fat.  In  churning  not  all  the  fat  can  be  recovered,  but 
the  loss  with  proper  methods  and  appliances  is  very  small. 
One  should  make  from  the  30  Ibs.  of  fat  about  36  Ibs.  of  but- 
ter of  the  composition  as  given.  To  calculate  the  per- 
centage of  overrun,  subtract  the  weight  of  butter-fat  from  the 
weight  of  the  butter  and  then  divide  the  difference  by  the 
weight  of  butter-fat  and  multiply  by  100. 

Formula : 

Wt.  of  butter— wt.  of  B.F. 

x  100  =  percentage  of  O.  R. 

weight  of  B.F. 


96  DAIRY  LABORATORY  GUIDE 

EXERCISE  8 

INFLUENCE  OF  ACIDITY  ON  THE  CHURNABILITY  OF  CREAM 

Object:  To  determine  the  influence  of  the  acidity  of  the 
cream  upon  the  loss  of  butter-fat  in  the  buttermilk,  on  the 
overrun,  and  on  the  texture  of  the  butter. 

Apparatus :  Two  lots  of  cream, — sweet  and  sour ;  churns ; 
workers;  scales;  outfits  for  determining  the  percentage  of 
butter-fat,  moisture,  and  salt. 

Steps:  1.  Number  the  churns  1  to  3  and  prepare  for 
churning. 

2.  Weigh  out  definite  amounts  of  sweet  cream  and  sour 
cream,  after  which  weigh  out  a  like  quantity  of  sweet  and 
sour  cream  in  equal  parts.     Retain  samples  of  each  lot  to  test 
for  acid  and  butter-fat. 

3.  Temper  each  lot  of  cream  to  54°F. ;  then  put  the  sweet 
cream  into  churn  No.  1,  the  properly  ripened  cream  into 
churn  No.  2,  and  the  mixed  cream  into  churn  No.  3. 

4.  Agitate  the  cream  until  the  butter  comes;  then  record 
the  length  of  time  required  to  churn,  after  which  remove  the 
buttermilk  and  retain  samples  to  test. 

5.  Temper  the  wash  water  to  56°  F.;  then  wash,  salt, 
work,  weigh,  and  pack  each  lot  in  the  same  way. 

6.  Record  the  time  required  to  churn,  make  all  of  the 
tests  for  butter-fat,  moisture,  and  salt;  then  figure  the  overrun 
for  each  lot. 

7.  Score  the  butter  from  each  lot  of  cream  after  several 
days  and  note  the  flavor  and  texture  of  each. 

Application:  1.  How  does  the  degree  of  acidity  affect 
the  time  of  churning? 

2.  In  which  lot  was  the  greatest  loss  of  butter-fat  in  the 
buttermilk?  Why? 


DAIRY  LABORATORY  GUIDE 


97 


3.  How  did  the  mixing  of  sweet  and  sour  cream  affect  the 
loss  of  butter-fat  in  the  buttermilk?     Why? 

4.  What  is  the  proper  degree  of  acidity  for  exhaustive 
churning? 

Data: 


Lot 

Per  ct. 
acidity 

Amt. 
cream 

Test 

Amt. 
B.  F. 

Per  ct. 
0.  R. 

Loss 
B.  M. 

Per  ct. 
moist. 

Perot, 
salt 

Time 

1 

o 

3 

Student's  Notes: 


98 


DAIRY  LABORATORY  GUIDE 


EXERCISE  9 

EFFECTS  OF  TEMPERATURE  IN  CHURNING 

Object:  To  determine  the  effects  of  variation  in  temper- 
ature of  cream  on  the  time  to  churn,  the  loss  of  butter-fat  in 
the  buttermilk,  the  moisture  content  of  the  butter,  the  per- 
centage of  overrun,  and  on  the  quality  of  the  butter. 

Apparatus :  Sample  of  cream,  churn,  worker,  testing  out- 
fits, thermometer,  and  scales. 

Steps:  1.  Test  the  cream  for  butter-fat  and  acid;  then 
divide  it  into  three  lots. 

2.  Temper  the  cream  for  lot  No.  1  to  48°  F.,  and  churn  it. 
Remove  the  buttermilk;  then  temper  the  wash  water  to  56°, 
and  wash,  salt,  weigh,  and  pack  the  butter  according  to  the 
preceding  directions.     Retain  a  sample  of  the  buttermilk  to 
test. 

3.  Temper  the  cream  for  lot  No.  2  to  54°  F.,  and  churn  it. 
Remove  the  buttermilk;  then  temper  the  wash  water  to  56° 
and  complete  the  work  as  in  step  No.  2. 

4.  Temper  the  cream  for  lot  No.  3  to  60°  F.,  and  churn 
it.     Remove  the  buttermilk;  then  temper  the  wash  water  to 
56°  and  complete  the  work  as  in  step  No.  2. 

5.  Record  the  length  of  the  time  to  churn  the  butter, 
test  each  sample  of  buttermilk,  make  all  computations,  and 
record  the  data. 

Data: 


Lot 

Per  ct. 
acid 

Amt. 
cream 

Test 

Amt. 
B.  F. 

Perct. 
0.  R. 

Loss 
B.  M. 

Per  ct. 

moist. 

Per  ct. 
salt 

Time 

1 

2 

3 

DAIRY  LABORATORY  GUIDE  99 

Application :  1 .  How  does  the  temperature  of  the  cream 
affect  the  time  of  churning?  The  loss  of  butter-fat  in  the 
buttermilk? 

2.  How  did  the  various  lots  of  butter  compare  as  to  the 
texture  of  the  butter?    Why? 

3.  What  influence  does  the  churning  temperature  have 
on  the  percentage  of  moisture  in  the  butter?     On  the  salt? 
On  the  overrun?     Why? 

4.  Did  each  lot  of  butter  require  the  same  amount  of 
working? 

Student's  Notes: 


100 


DAIRY  LABORATORY  GUIDE 


EXERCISE  10 

VARIATIONS  IN  TEMPERATURE  OF  WASH  WATER  ON  BUTTER 

Object :  To  determine  the  effects  of  the  variation  in  tem- 
perature of  the  wash  water  on  the  moisture,  the  salt  content, 
and  the  texture  of  the  butter. 

Apparatus :  A  quantity  of  cream,  churns,  workers,  test- 
ing outfits,  thermometer,  and  scales. 

Steps:  1.  Ripen  a  quantity  of  cream  to  the  proper 
degree  for  churning  and  divide  it  into  three  lots  equal  in 
amount. 

2.  Churn  each  lot  of  cream  the  same;  remove  the  butter- 
milk and  retain  samples  to  test. 

3.  Temper  the  wash  water  to  48°  F.,  and  wash  lot  No.  1. 

4.  Temper  another  lot  of  wash  water  to  56°  F.,  and 
wash  lot  No.  2. 

5.  Temper  another  lot  of  wash  water  to  60°  F.  and  wash 
lot  No.  3. 

6.  Remove  the  butter  to  the  workers;  then  salt,  work, 
weigh,  and  pack  each  lot  alike. 

7.  Compute  the  overrun;  then  determine  the  percentage 
of  moisture,  the  percentage  of  salt,  and  the  texture  of  each  lot 
of  butter. 

Data: 


Lot 

Per  ct. 
acid 

Amt. 
cream 

Test 

Amt. 
B.  F. 

Amt. 
butter 

Per  ct. 
O.  R. 

Loss 
B.  M. 

Per  ct. 
moist. 

Per  ct. 
salt 

1 

2 

3 

DAIRY  LABORATORY  GUIDE  101 

Application:  1.  How  did  the  various  temperatures  of 
the  wash  water  affect  the  overrun?  The  moisture  content? 
The  salt  content?  Why? 

2.  Under  what  conditions  would  it  be  well  to  wash  butter 
at  48°F.?    At  56°F.?    At  60°F.? 

3.  How  was  the  texture  of  the  butter  affected  by  the 
extreme  temperatures? 

Student's  Notes : 


102 


DAIRY  LABORATORY  GUIDE 


EXERCISE  11 

THE  DISTRIBUTION  OF  SALT  IN  BUTTER 

Object:  To  determine  the  effects  of  uneven  distribution 
of  salt  upon  the  color,  grade,  and  the  keeping  quality  of  butter. 

Apparatus:    Cream,  and  churning  outfit. 

Steps:  1.  Ripen  a  quantity  of  cream  to  the  proper 
degree  of  acidity,  weigh  out  a  definite  amount,  and  temper  it 
to  54°F. 

2.  Complete  the  churning  as  usual;  then  divide  the 
butter  into  two  lots. 

3.  Remove  lot  No.  1  to  the  worker;  then  apply  the  salt 
and  work  it  in  evenly. 

4.  Remove  lot  No.  2  to  the  worker;  then  sprinkle  the  salt 
unevenly  and  do  not  work  it  in  thoroughly. 

5.  Test  each   lot  of  butter  for  moisture  and  salt;  then 
store  it.     Examine  the  butter  at  intervals  to  note  the  score. 

Data: 


Lot 

1 

2 

Hours 

24 

48 

72 

24 

48 

72 

Flavor 

Texture 

Color 

Per  cent  salt 

Per  cent  moisture 

Grade 

Market  value 

DAIRY  LABORATORY  GUIDE 


103 


Application:     1.       How 

does  the  uneven  distribution 
of  salt  affect  the  color  of  the 
butter?  The  grade?  The 
market  value? 

2.  Compute  the  returns 
in  one  year  at  current  prices 
for  butter  from  a  herd  of  ten 
cows  averaging  150  pounds 
of  butter-fat  each,  grading 
the  butter  according  to  the 
findings  in  this  experiment. 

Student's  Notes: 


Fig,  15.    A  butter  mold. 


104 


DAIRY  LABORATORY  GUIDE 


EXERCISE  12 

THE  EFFECT  OF  OVERWORKING  BUTTER 

Object:  To  determine  the  effects  upon  the  texture, 
moisture  content,  and  the  salt  content  of  butter  by  overwork- 
ing. 

Apparatus :     Cream,  and  churning  outfit. 

Steps:  1.  Ripen  a  quantity  of  cream  to  the  proper 
degree  of  acidity,  weigh  out  a  definite  amount,  and  temper  to 
54°  F. 

2.  Complete  the  churning  as  usual;  then  divide  the  but- 
ter into  two  lots. 

3.  Remove  lot  No.  1  to  the  worker,  salt  evenly  and  then 
work  the  butter  just  enough. 

4.  Remove  lot  No.  2  to  the  worker,  salt  evenly;  then 
overwork  the  butter. 

5.  Test  each  lot  of  butter  for  moisture  and  salt;  then 
store  and  examine  it  at  subsequent  intervals  to  note  the  score. 

Data: 


Lot 

i 

2 

Hours 

24 

48 

72 

24 

48 

72 

Flavor 

Texture 

Color 

Per  cent  salt 

Per  cent  moisture 

Grade 

• 

Market  value 

DAIRY  LABORATORY  GUIDE  105 

Application:     1.     What  effect  has  working  upon  the  dis- 
tribution of  salt? 

2.  What  causes  mottles  in  butter? 

3.  How  does  overworking  affect  the  grain  or  texture  of 
butter? 

4.  How  may  one  know  when  butter  is  overworked? 

5.  Compute  the  returns  in  one  year  from  a  cow  produc- 
ing 150  pounds  of  butter-fat,  at  current  prices  for  butter 
graded  according  to  the  findings  in  this  experiment. 

Student's  Notes: 


106 


DAIRY  LABORATORY  GUIDE 


EXERCISE  13 

INFLUENCE  OF  THE  GRADE  OF  CREAM  ON  THE 
QUALITY  OF  BUTTER 

Object:  To  determine  the  influence  of  different  grades 
of  cream  on  the  grade,  the  market  value,  and  the  keeping 
quality  of  butter. 

Apparatus:  Two  lots  of  cream,  grading  first  and  second; 
and  a  churning  outfit. 

Steps:  1.  Secure  for  lot  No.  1  a  small  amount  of  first- 
grade  cream,  which  is  reasonably  sweet  and  of  clean  flavor, 
with  acidity  not  over  .2%.  Temper  this  to  54°F.  and  com- 
plete the  churning  as  usual. 

2.  Secure  for  lot  No.  2  a  small  amount  of  second-grade 
cream,  which  is  reasonably  free  from  objectionable  odors  and 
flavors,  with  acidity  over.  2%.    Temper  this  to  54°F. ,  complete 
the  churning,  wash,  salt,  work,  and  store  the  same  as  lot  No.  1. 

3.  Examine  the  butter  at  intervals  and  determine  the 
grade  and  keeping  quality  of  the  butter. 

Data: 


Lot 

1 

2 

Hours 

24 

48 

72 

24 

48 

72 

Flavor 

Texture 

Color 

Per  cent  salt 

Per  cent  moisture 

Grade 

Market  value 

DAIRY  LABORATORY  GUIDE  107 

Application:     1.     What  is  the  immediate  difference  in 
the  butter  from  each  lot  of  cream? 

2.  How  long  would  hand-separator  cream  keep  before  it 
would  grade  second  in  winter?     In  the  summer? 

3.  What  inducement  do  many  creameries  give  to  insure 
frequent  delivery  of  cream?    Why? 

4.  Compute  the  value  of  1000  pounds  of  butter  on  the 
Chicago  market  made  from  each  grade  of  cream. 

5.  How  much  would  a  farmer  gain  in  one  year  from  a 
herd  of  five  cows,  averaging  150  pounds  of  butter-fat  each,  if 
all  of  the  cream  graded  first  and  the  creamery  paid  2c  per 
pound  premium  on  the  butter-fat? 

6.  How  can  a  creamery  afford  to  pay  a  premium  on  first- 
grade  cream? 

Student's  Notes: 


PART  FOUR 


THE  MARKETING  OF  DAIRY  PRODUCTS 

The  marketing  of  the  finished  product  and  the  profitable 
utilization  of  the  by-products  is  one  of  the  important  branches 
of  any  industry.  In  the  past,  the  dairy  instruction,  for  the 
most  part,  has  been  applied  to  the  production,  care,  and  man- 
ufacture of  a  variety  of  products,  with  very  little  attention 
given  to  the  marketing  end  of  the  business. 

There  are  a  great  many  marketable  forms  of  dairy  prod- 
ucts and  each  one  is  sold  on  a  different  basis.  This  condition 
requires  a  knowledge  of  how  to  standardize,  classify,  and 
grade;  how  to  judge,  compare  values,  and  market  the  prod- 
ucts; and  how  to  compute  the  returns. 


110 


DAIRY  LABORATORY  GUIDE 


Fig.  16.  A  milk 
scale  s  used  in 
keeping  milk 
records. 

Data: 


EXERCISE  1 

VARIATION  OF  BUTTER-FAT  IN  MARKET  MILK 

Object:  To  determine  the  value  of  market 
milk  containing  varying  percentages  of  but- 
ter-fat. 

Apparatus:  Samples  of  milk,  scales,  and 
testing  outfit. 

Steps:  1.  Determine  the  percentage  of 
butter-fat  in  the  milk  from  different  patrons. 

2.  Determine   the   average   weight   of  a 
quart  of  milk  by  weighing  several  samples  on 
the  scales. 

3.  Determine  the  number  of  quarts  in  a 
hundred  pounds  of  milk  testing  as  above,  and 
the  market  value  when  retailed  at  local  prices. 


Patron 

Amount  of 
milk 

Per   cent 
test 

Number  of 
quarts 

Selling 
price 

Total 
returns 

1 

2 

3 

4 

Application:  1.  What  will  be  the  cash  value  of  the 
milk  from  a  cow  giving  5000  pounds  of  4%  milk  in  one  year 
when  retailed  at  local  prices? 

2.  What  is  the  weight  of  a  quart  of  milk  testing  4%?     A 
gallon? 

3.  How  does  the  percentage  of  butter-fat  influence  the 
weight?    The  price? 


DAIRY  LABORATORY  GUIDE  111 

Student's  Notes: 


112 


DAIRY  LABORATORY  GUIDE 


EXERCISE  2 

VARIATION  OF  BUTTER-FAT  IN  MARKET  CREAM 

Object:  To  determine  the  market  value  of  milk  when 
sold  as  cream  containing  different  percentages  of  butter-fat. 

Apparatus :  Samples  of  milk  and  cream,  scales,  and  test- 
ing outfit. 

Steps:  1.  Secure  samples  of  cream  from  the  separator 
and  determine  the  percentage  of  butter-fat. 

2.  Determine  the  average  weight  of  cream  containing 
varying  percentages  of  butter-fat  by  weighing  a  number  of 
samples  on  the  scales. 

3.  Determine  the  market  value  of  a  hundred  pounds  cf 
milk  sold  at  local  prices  for  sweet  cream  testing  as  the  above. 
Record  data  below. 

4.  Determine  the  value  of  the  skimmilk,  estimated  at 
Ytf,  per  pound. 

To  determine  the  amount  of  cream.  Rule:  Multiply 
the  amount  of  milk  by  the  test  and  divide  the  product  by  the 
percentage  of  butter-fat  in  the  cream. 

To  obtain  the  amount  of  skimmilk.  Rule:  Subtract  the 
amount  of  cream  from  the  amount  of  milk,  assuming  no  loss 
of  butter-fat  in  the  skimmilk. 

Data: 


Patron 

Amt.  of 
cream 

Per  cent 
test 

No. 
quarts 

Selling 
price 

Value  of 
cream 

Value 
skimmilk 

Total 
returns 

1 

2 

3 

4 

DAIRY  LABORATORY  GUIDE  113 

Application:  1.  If  the  product  of  a  cow  giving  5000 
pounds  of  4%  milk  in  one  year  is  sold  as  20%  cream  at  local 
prices,  what  will  be  the  total  returns,  estimating  the  skimmilk 
at  J^c  per  pound? 

2.  How  would  a  variation  in  the  test  of  the  cream  influ- 
ence the  selling  price? 

Student's  Notes: 


114 


DAIRY  LABORATORY  GUIDE 


EXERCISE  3 

MARKETING  BUTTER  AND  BY-PRODUCTS 

Object:  To  determine  the  market  value  of  milk  when 
sold  as  butter  and  by-products. 

Apparatus :    Samples  of  milk,  and  testing  outfit. 

Steps:  1.  Determine  the  percentage  of  butter-fat  in 
milk  from  different  patrons. 

2.  Determine  the  amount  of  20%  cream  and  the  skim- 
milk  from  100  pounds  of  milk  according  to  the  tests. 

3.  Determine  the  amount  of  butter  from  each  patron, 
allowing  20%  overrun. 

4.  Find  the  total  value  of  the  butter  and  the  skimmilk  at 
local  prices  for  butter,  estimating  the  value  of  the  skimmilk 
at  50c  per  hundredweight. 

Data: 


Patron 

Amount 
cream 

Per  ct. 
test 

Pounds 
butter 

Selling 
price 

Value 
butter 

Value 
skimmilk 

Total 
returns 

1 

2 

3 

4 

Application:  1.  If  the  product  of  a  cow  giving  5000 
pounds  of  4%  milk  be  sold  as  butter  at  local  prices,  what  will 
be  the  cash  returns,  estimating  the  skimmilk  and  the  butter- 
milk at  50c  per  hundredweight? 

2.  How  much  will  the  skimmilk  be  worth  per  hundred 
when  fed  to  calves?  To  swine?  To  poultry? 


DAIRY  LABORATORY  GUIDE  115 

Student's  Notes: 


116 


DAIRY  LABORATORY  GUIDE 


EXERCISE  4 

THE  MARKETING  OF  ICE  CREAM 

Object :  To  determine  the  value  of  milk  containing  vary- 
ing percentages  of  butter-fat  when  marketed  as  ice  cream  and 
skimmilk. 

Apparatus :        Samples  of  milk,  scales,  and  testing  outfit. 

Steps :  1 .  Determine  the  percentage  of  butter-fat  in  the 
milk  from  the  different  patrons. 

2.  Determine  the  number  of  quarts  of  25%  cream  from 
100  pounds  of  milk  from  each  patron. 

3.  Determine  the  number  of  quarts  of  ice  cream  that  can 
be  made  from  the  cream  of  each  patron,  allowing  a  30%  over- 
run. 

4.  Find  the  total  market  value  of  the  ice  cream  at  local 
prices  and  the  skimmilk  at  ^c  per  pound. 

Data: 


Patron 

Amount 
cream 

Test 

Quarts 
ice  cr. 

Selling 
price 

Value 
ice  cr. 

Value 
skimmilk 

Total 

returns 

1 

2 

3 

4 

Application:  1.  If  the  product  of  a  cow  giving  5000 
pounds  of  4%  milk  in  one  year  be  marketed  as  ice  cream,  what 
will  be  the  total  cash  returns  at  local  prices,  estimating  the 
skimmilk  at  50c  per  hundred? 

2.  Which  form  of  marketing  the  products  of  the  herd  will 
bring  the  dairyman  the  largest  total  cash  returns? 


DAIRY  LABORATORY  GUIDE  117 

3.  In  case  the  by-products,  skimmilk,  and  buttermilk 
were  fed  to  poultry,  which  method  would  bring  the  largest 
:otal  returns? 

Student's  Notes: 


118 


DAIRY  LABORATORY  GUIDE 


EXERCISE  5 

THE  STANDARDIZING  OF  DAIRY  PRODUCTS 

Object :  To  standardize  market  milk  or  cream  with  vary- 
ing percentages  of  butter-fat  to  a  product  of  a  definite  stand- 
ard. 

Apparatus:  A  quantity  of  milk,  cream,  and  skimmilk, 
two  shotgun  cans,  milk  scales,  and  testing  outfit. 

Steps:  1.  Determine  the  percentage  of  butter-fat  in 
the  products  to  be  standardized. 

The  accompanying  diagram 
'3  devised  by  Pearson  will  assist  in 
determining  the  quantity  of  each 
product  necessary  to  make  up  a 
definite  amount  of  the  standard 
product. 

/3  In  using  the  diagram,  place 

the   percentage  of   test  of    the 

milk,  cream,  or  skimmilk,  to  be  standardized  at  the  left-hand 
corners,  and  the  test  of  the  desired  product  in  the  center  of 
the  square.  The  difference  between  the  test  of  the  desired 
product  in  the  center  and  those  to  be  standardized  at  the 
left-hand  corners  is  placed  at  the  right-hand  corners.  These 
figures  represent  the  proportions  of  the  products  to  use  in 
standardizing. 

2.     Standardize  two  lots  of  milk  containing  different  per- 
centages of  butter-fat  to  a  product  of  a  definite  standard. 
Data: 


Lot 

Test 

Standard  test 

Proportions 

Amounts 

1 

2 

DAIRY  LABORATORY  GUIDE 


119 


3.     Standardize  milk  or  cream  to  a  product  of  a  definite 
standard  by  using  cream. 

Data: 


Lot 

Test 

Standard  test 

Proportions 

Amounts 

1 

2 

4.     Standardize  milk  or  cream  to  a  product  of  a  definite 
standard  by  using  skimmilk. 

Data: 


Lot 

Test 

Standard  test 

Proportions 

Amounts 

1 

2 

Application:     1.     Of  what  advantage  to  the  milkman  is 
standardization? 

2.  Why  is  it  necessary  to  standardize  milk  and  cream? 

3.  How  much  2.5%  and  6%  milk  will  it  require  to  stand- 
ardize 210  pounds  of  milk  to  4%?     Prove  the  accuracy  of  the 
computation. 

4.  Standardize  334  pounds  of  6.4%  milk  from  3.5%  milk 
and  20%  cream. 

5.  How  much  skimmilk  testing  .02%  will  be  required  to 
standardize  150  Ibs.  of  4%  milk  from  milk  testing  7.2%? 

6.  How    much    gravity    cream   testing   15%    will   be 
required  to  standardize  250  pounds  of  25%  cream  from  cream 
testing  40%? 


120  DAIRY  LABORATORY  GUIDE 

7.  What  will  be  the  increased  net  returns* at  6c  per  quart, 
from  a  cow  giving  5000  Ibs.  of  6%  milk  in  one  year,  when 
standardized  to  4%  by  using  skimmilk  worth  50c  per  hun- 
dred? 

Student's  Notes: 


DAIRY  LABORATORY  GUIDE  121 

EXERCISE  6 

THE  DETERMINATION  OF  CREAMERY  DIVIDENDS 

Object:  To  determine  the  dividends  on  a  butter-fat 
basis  of  patrons  selling  cream  to  a  co-operative  creamery  for 
a  given  period. 

Apparatus:     Samples  of  cream,  and  testing  outfit. 

Steps:  1.  Determine  the  percentage  of  butter-fat  in 
the  cream  of  four  patrons. 

2.  To  determine  the  amount  of  butter-fat  delivered  by 
each  patron,  multiply  the  amount  of  cream  delivered  by  the 
test. 

3.  To  determine  the  amount  of  butter  manufactured, 
allow  20%  overrun,  with  no  loss  of  butter-fat  in  the  butter- 
milk. 

4.  To  determine  the  value  per  pound  of  butter-fat,  divide 
the  total  receipts  from  butter  sales  at  local  prices  by  the 
total  pounds  of  butter-fat  delivered  for  the  period. 

5.  To  determine  the  dividends  due  each  patron,  multiply 
the  pounds  of  butter-fat  each  delivered  for  the  period  by  the 
net  price  per  pound  of  butter-fat.      Assume  the  operating 
expenses  of  the  creamery  to  be  $125  for  the  period. 

Data: 


Patron 

Amt.  cream 
delivered 

Test 

Pounds 
B.  F. 

Net  price 
butter-fat 

Dividend 
due 

1 

2 

3 

4 

122  DAIRY  LABORATORY  GUIDE 

Application:  1.  What  will  be  the  dividends  due  each 
patron  for  a  given  period  when  No.  1  delivers  1200  pounds  of 
first-grade  cream,  No.  2  delivers  3000  pounds,  No.  3  delivers 
2500  pounds,  and  No.  4  delivers  1800  pounds,  testing  accord- 
ing to  the  above  samples?  Assume  $125  for  running  expenses 
and  J^c  per  pound  of  butter-fat  for  a  sinking  fund. 

2.  What  will  be  the  net  dividend  for  each  patron  where 
second-grade  cream  is  delivered  and  the  butter  from  it  sells 
for  4c  per  pound  below  market  quotations  for  Extras? 

3.  What  is  a  sinking  fund?    How  is  the  net  price  per 
pound  of  butter-fat  determined  for  the  period? 

4.  What  conditions  make  it  possible  for  the  price  per 
pound  of  butter-fat  to  be  more  than  the  selling  price  for 
butter? 

Student's  Notes: 


APPENDIX 

THE  SCORING  OF  BUTTER 

The  different  butter  markets  require  some  standard  of 
perfection  whereby  certain  qualities  in  the  butter  can  be 
measured  and  compared.  This  has  led  to  the  adoption  of 
a  system  of  scoring  based  upon  flavor,  texture,  color,  salt,  and 
package,  with  relative  values  attached  to  each  point. 

The  score  card  is  used  by  the  judge  as  a  yardstick  and  as  a 
record  in  case  a  number  of  samples  are  judged  at  a  time. 

BUTTER  SCORE  CARD 


Scale 

Score 

Remarks 

Flavor 

45 

Texture 

25 

Color 

15 

Salt 

10 

Package 

5 

Total 

100 

The  butter  judge  uses  a  trier  to  remove  a  plug  of  butter 
from  the  package  to  be  scored.  The  sample  is  then  held 
close  to  the  nose  immediately  after  being  withdrawn  in  order 
to  detect  the  aroma,  which  is  a  very  volatile  odor.  The 


124  DAIRY  LABORATORY  GUIDE 

aroma  of  good  butter  is  extremely  delicate  and  passes  away 
soon  after  the  sample  is  removed  from  the  package. 

DESCRIPTIVE  TERMS 
Flavor.    The  flavor  is  the  most  important  quality  in 

butter,  and  is  determined  by  the  sense  of  smell  and  taste. 
The  aroma  is  detected  by  the  sense  of  smell  and  the  flavor  by 
the  sense  of  taste.  The  judge  combines  these  two  and  notes 
the  defects  in  order  to  form  a  judgment  on  flavor. 

Perfect  flavor  in  the  highest  grade  of  butter  made  from 
the  very  best  cream  is  described  as  being  clean,  sweet,  and 
nutty.  It  should  have  a  pleasant,  delicate  aroma,  char- 
acteristic of  clean,  well-ripened  cream. 

Stable  flavor  is  characteristic  of  cow  stables,  and  is  com- 
monly caused  by  admixture  of  dirt  or  by  milking,  straining, 
or  keeping  the  milk  too  long  in  a  dirty  stable. 

Unclean  flavor  results  from  dirty  pails,  strain- 
ers, and  other  utensils,  or  from  careless  methods 
of  handling  the  milk. 

Rancid  flavor  is  caused  by  overripened  cream 
or  when  milk,  cream,  or  butter  is  kept  too  long, 
especially  when  kept  in  the  sunshine. 

Curdy  flavor  is  often  due  to  adding  over- 
ripened  starters  to  the  cream,  or  to  incomplete 
removal  of  the  buttermilk  when  washing  the 
butter. 

Weedy  flavor  is  due  to  the  cows  eating  weeds 
in  the  pasture.  It  may  come  from  feeding  the 
cows  onions,  cabbage,  or  turnips,  or  it  may  come  from  ex- 
posing the  milk  and  the  cream  in  surroundings  where  de- 
cayed vegetable  odors  are  present. 

Oily  flavor  may  result  from  churning  the  cream,  wash- 
ing or  working  the  butter  at  too  high  a  temperature.  It  may 


DAIRY  LABORATORY  GUIDE  125 

result  from  using  too  much  or  too  old  butter  coloring.  The 
cause  is  sometimes  attributed  to  certain  kinds  of  bacteria. 

Cowy  flavor  suggests  animal  odors,  and  may  appear  in  the 
spring  when  the  cows  are  first  turned  to  pasture.  It  may 
appear  in  milk  from  a  cow  that  is  sick  or  in  a  feverish  condi- 
tion. 

Texture.  Texture  refers  to  the  grain  and  to  the  body  of 
the  butter.  It  is  determined  by  the  appearance  and  feeling 
of  the  sample  on  the  trier.  The  globules  of  fat  cohere  to  one 
another  rather  loosely  and  irregularly  during  the  churning. 
They  retain  this  same  position  in  the  body  of  the  finished 
product,  unless  the  cream  is  churned  too  warm  or  the  butter 
is  washed  and  worked  improperly. 

Perfect  texture  allows  the  butter  granules  to  retain  their 
individuality,  and  when  broken  apart  the  fractured  ends  will 
appear  like  broken  steel.  It  also  allows  the  back  of  the  trier 
to  be  free  from  a  greasy  appearance  when  withdrawn  from  the 
sample.  A  good  body  will  show  firmness  under  the  thumb 
when  examined  at  ordinary  temperatures. 

Salvy  texture  is  due  to  washing  or  working  the  butter  at 
too  high  temperatures  or  to  overworking.  These  destroy 
the  grain,  which  makes  the  butter  appear  sticky  or  greasy 
and  pull  apart  like  gum. 

Tallowy  texture  results  from  the  presence  of  much  hard 
fats  in  the  butter-fat,  due  to  the  cow's  being  too  long  in  lacta- 
tion or  to  chilling  the  butter  in  extremely  cold  wash  water. 

Poor  grain  refers  to  a  lack  of  proper  mechanical  methods 
in  making  the  butter. 

Weak  body  refers  to  butter  which  is  soft  and  salvy  in 
texture  and  in  which  the  moisture  is  high  or  not  thoroughly 
incorporated.  It  may  be  the  result  of  the  feed  the  animal 
receives,  as  green  grass,  or  from  too  high  temperatures. 

Color.     The  natural  color  of  butter  varies  from  a  light 


126  DAIRY  LABORATORY  GUIDE 

straw  to  a  deep  yellow,  depending  upon  the  breed  of  the  cow, 
the  feed  she  receives,  and  the  season  of  the  year.  The  aver- 
age market  demands  a  light  straw  color  similar  to  that  produc- 
ed by  June  pasturage.  A  uniform  color  is  demanded,  which 
makes  it  necessary  to  use  artificial  coloring  in  varying 
amounts. 

Perfect  color  is  a  lively  straw  yellow,  uniform  and  solid 
throughout. 

Mottles  are  uneven  colors  of  light  and  dark  spots,  waves, 
or  streaks.  The  high  colors  are  caused  by  the  attraction  of 
moisture  from  the  undissolved  salt.  The  light  portions  may 
result  from  the  action  of  the  salt  upon  the  buttermilk  remain- 
ing in  the  butter. 

White  Specks  are  due  either  to  particles  of  casein  result- 
ing from  overripe  cream  or  overripe  starter,  or  to  dried 
particles  of  cream  caused  from  lack  of  stirring  during  ripening. 

Salt.  The  quantity  of  salt  usually  varies  from  none  at 
all  to  an  ounce  per  pound  of  butter-fat.  The  important  thing 
is  to  have  the  salt  uniformally  distributed  throughout  the 
butter  and  thoroughly  dissolved. 

Flat  is  the  term  used  to  describe  the  lack  of  salt. 

Gritty  refers  to  undissolved  salt,  and  is  a  most  objection- 
able defect. 

Package.  This  refers  to  the  appearance  of  the  butter  on 
the  market.  The  trade  desires  the  butter  to  be  put  into  a 
tub,  jar,  or  print  which  is  clean,  neat,  and  attractive. 

CLASSIFICATION  OF  BUTTER 

It  is  customary  in  local  markets  to  classify  butter  under 
the  general  heads  of  Creamery,  Dairy,  and  Process  butter; 
however,  the  large  mercantile  exchanges  include  a  more 
detailed  system. 


DAIRY  LABORATORY  GUIDE  127 

The  Chicago  Market. 

The  Chicago  Butter  and  Egg  Board  classifies  the  butter 
handled  on  their  markets  as  Creamery,  Dairy,  Ladle,  Reno- 
vated, Packing  Stock,  and  Grease  Butter. 

Creamery  Butter.  Butter  offered  under  this  classifica- 
tion shall  have  been  made  in  a  creamery  from  cream  obtained 
by  the  separator  system,  or  gathered  cream. 

Dairy  Butter.  Butter  offered  under  this  classification 
shall  be  such  as  is  made,  salted  and  packed  by  the  dairyman, 
and  offered  in  its  original  package. 

Ladle  Butter.  Butter  offered  under  this  classification 
shall  have  been  collected  in  rolls,  lumps,  or  in  whole  packages, 
and  reworked  by  the  dealer  or  shipper. 

Renovated  Butter.  Butter  offered  under  this  classifica- 
tion shall  be  made  by  taking  butter  and  melting  the  same, 
and  rechurning  with  fresh  milk,  cream,  or  skimmilk,  or  other 
equivalent  process. 

Grease  Butter.  Shall  consist  of  all  grades  of  butter  below 
Fourths,  free  from  adulteration. 

GRADES. 

Extras  shall  consist  of  the  highest  grade  of  butter,  pro- 
duced during  the  season  when  made,  scoring  93  points  or 
higher. 

Flavor.  Must  be  quick,  fine,  fresh  and  clean  if  of  fresh 
make,  and  good,  sweet  and  clean  if  held. 

Body.  Must  be  firm  and  solid,  with  a  perfect  grain  or 
texture,  free  from  salviness. 

Color.     Must  be  uniform,  neither  too  light  nor  too  high. 

Salt.  Well  dissolved,  thoroughly  worked  in,  not  too  high 
nor  too  light  salted. 

Package.     Good  and  sound  as  required  in  classification. 


128  DAIRY  LABORATORY  GUIDE 

Extra  Firsts  shall  be  a  grade  just  below  Extras,  scoring  90 
points  or  higher,  lacking  somewhat  in  quick  flavor,  which, 
however,  must  be  good,  sweet,  clean  and  fresh,  if  of  fresh 
make,  and  sweet  and  clean  if  held.  All  other  requirements 
being  the  same  as  in  Extras. 

Firsts  shall  be  a  grade  just  below  Extra  Firsts,  scoring  87 
points  or  higher,  lacking  in  flavor,  which,  however,  must  be 
good,  sweet  and  clean.  All  other  requirements  the  same  as 
in  Extra  Firsts. 

Package.     Good  and  uniform. 

Seconds  shall  consist  of  a  grade  just  below  Firsts,  scoring 
80  points  or  higher. 

Flavor.     Must  be  fairly  good  and  sweet. 

Body.     Must  be  sound  and  smooth  boring. 

Color.  Fairly  good,  although  it  may  be  somewhat  irregu- 
lar. 

Salt.     May  be  irregular,  high  or  light  salted. 

Package.     Same  as  required  in  Firsts. 

Thirds  shall  consist  of  butter  below  Seconds,  scoring  75 
points  or  higher. 

Flavor.  Reasonably  good,  may  show  strong  tops  and 
side. 

Body.     Not  smooth  boring. 

Color.     Mixed  or  streaked. 

Salt.     Irregular. 

Package.     Miscellaneous. 

Fourths  shall  be  a  grade  below  Thirds  and  may  consist  of 
promiscuous  lots,  may  be  off-flavored  and  strong  tops  and 
sides. 

Body.     Not  required  to  draw  a  full  trier. 

Color.     May  be  irregular. 

Package.     Any  kind  of  package  mentioned  at  time  of  sale. 


DAIRY  LABORATORY  GUIDE  129 

Packing  Stock  shall  consist  of  three  grades,  viz.,  Extras, 
Number  One  and  Number  Two. 

Extras  in  Packing  Stock  shall  be  original  butter  without 
additional  moisture  or  salt,  sweet  and  sound,  packed  in  new 
barrels  having  wooden  heads  in  both  ends,  or  in  new  tubs, 
both  to  be  parchment  paper  lined,  barrels  and  tubs  to  be 
packed  full. 

Number  One  Packing  Stock  shall  be  original  butter  with- 
out additional  moisture  or  salt,  sweet  and  sound.  May  be 
packed  in  different  kinds  of  barrels,  tierces,  pails,  tubs  or  good 
clean  boxes,  may  be  without  paper  lining,  may  be  packed  in 
two-headed  or  cloth-covered  barrels. 

Number  Two  Packing  Stock  shall  be  grade  or  quality 
above  Grease  Butter  and  packed  in  any  or  all  kinds  of  pack- 
ages. 

PACKAGES  To  BE  USED. 

Creamery.     Tubs,  hardwood,  about  60  Ibs.  (for  Extras 
shall  be  standard  white  ash  60-lb.  tubs). 
Dairy.    Tubs  of  varying  size. 
Ladles.    Tubs  of  varying  size. 
Renovated.    Tubs  of  varying  size. 
Roll.    Any  style  or  size  of  package. 
Grease.    Any  style  or  size  of  package. 

The  New  York  Market. 

The  New  York  Mercantile  Exchange  classifies  the  butter 
handled  on  their  markets  as  Creamery,  Process,  Factory, 
Packing  Stock,  and  Grease  Butter. 

Creamery  Butter  offered  under  this  classification  shall 
have  been  made  in  a  creamery  from  cream  separated  at  the 
creamery  or  gathered  from  the  farmers. 


i::  ;  DAIRY  LABORATORY  GUIDE 

Dairy  Butter  includes  all  butter  made  on  the  farm,  and 
salted,  packed,  and  sold  in  the  original  packages  by  the  dairy- 
man. 

Process  Butter  offered  under  this  classification  shall  be 
such  as  is  made  by  melting  butter,  clarifying  the  fat  therefrom 
and  rechurning  the  same  with  fresh  milk,  cream,  or  skimmilk, 
or  other  similar  process. 

Factory  Butter  offered  under  this  classification  shall  be 
such  as  is  collected  in  rolls,  lumps,  or  in  whole  packages  and 
reworked  by  the  dealer  or  the  shipper. 

Packing  Stock.  Butter  offered  under  this  classification 
shall  be  original  farm-made  butter  in  rolls,  lumps,  or  other- 
wise, without  additional  moisture  or  salt. 

Grease  Butter  shall  comprise  all  classes  of  butter  grading 
below  Thirds,  or  of  packing  stock  grading  below  No.  3,  as 
hereinafter  specified,  free  from  adulteration. 

GRADES  OF  BUTTER 

The  grading  of  butter  on  the  market  is  determined  largely 
by  the  score.  The  standard  official  rules  adopted  by  the 
New  York  Mercantile  Exchange  stipulate  that  Creamery, 
Process,  and  Factory  butters  shall  be  graded  as  Extras,  Firsts, 
Seconds,  and  Thirds;  and  Packing  Stock  shall  be  graded  as 
No.  1,  No.  2,  and  No.  3.  The  grades  must  conform  to  the 
following  requirements : 

1.  Extras  shall  comprise  the  highest  grade  of  butter 
obtainable  in  the  season  when  offered,  under  the  various 
classifications.  Ninety  per  cent  shall  conform  to  the  follow- 
ing standard;  the  balance  shall  grade  below  Firsts. 

Flavor.  In  Class  A,  fresh  butter,  current  make,  must  be 
fine,  sweet,  fresh  and  clean.  Class  B  must  be  reasonably  fine, 
sweet,  fresh,  and  clean. 


DAIRY  LABORATORY  GUIDE  131 

If  held,  in  Class  A,  flavor  must  be  fine,  sweet,  and  clean. 
In  Class  B,  must  be  reasonably  fine,  sweet,  and  clean. 

Texture  must  be  firm  and  uniform. 

Color.     A  light  straw  shade,  even  and  uniform. 

Salt.     Medium  salted. 

Package.     Sound,  good,  uniform,  and  clean. 

Score.  In  Class  A,  93  points  or  higher.  In  Class  B,  91 
points  or  higher. 

2.  Firsts  shall  be  a  grade  just  below  Extras,  and  must  be 
good  butter  for  the  season  when  offered,  under  the  various 
classifications.     Ninety  per  cent  shall  conform  to  the  follow- 
ing standard;  the  balance  shall  not  grade  below  Seconds. 

Flavor.  Must  be  good,  sweet,  clean  and  fresh,  if  of  cur- 
rent make,  in  Class  A;  and  be  good,  sweet,  reasonably  clean 
and  fresh,  if  of  current  make,  in  Class  B. 

If  held,  must  be  good,  sweet  and  clean  in  Class  A;  and 
good,  sweet  and  reasonably  clean  in  Class  B. 

Texture.     Must  be  firm  and  fairly  uniform. 

Color.  Reasonably  uniform,  neither  very  high  nor  very 
low. 

Salt.     May  be  reasonably  high,  light,  or  medium. 

Package.     Sound,  good,  uniform,  and  clean. 

Score.  In  Class  A,  88  to  92  points.  In  Class  B,  86  to 
90  points. 

3.  Seconds  shall  be  a  grade  just  below  Firsts. 
Flavor.     Must  be  reasonably  good. 

Texture.  If  Creamery,  must  be  solid  boring.  If  Factory 
or  Process,  must  be  90  per  cent  solid  boring. 

Color.     Fairly  uniform,  but  may  be  mottled. 

Salt.     May  be  high,  medium,  or  light. 

Package.     Good  and  uniform. 

Score.  In  Class  A,  83  to  87  points.  In  Class  B,  81  to  85 
points. 


132  DAIrtY  LABORATORY  GUIDE 

4.  Thirds  shall  be  a  grade  just  below  Seconds,  and  may 
consist  of  promiscuous  lots. 

Flavor.     May  be  off-flavored  and  strong  on  tops  and  sides. 

Texture.     Not  required  to  draw  a  full  trier. 

Color.     May  be  irregular  or  mottled. 

Salt.     High,  light,  or  irregular. 

Package.    «Any  kind  of  package  mentioned  at  time  of  sale. 

Score.  In  Class  A,  77  to  82  points.  In  Class  B,  75  to  80 
points. 

No.  1  Packing  Stock  shall  be  sweet  and  sound,  packed  in 
large,  new  or  good  second-hand  barrels,  having  a  wooden  head 
in  each  end,  or  in  new  tubs,  either  to  be  parchment  paper 
lined.  Barrels  and  tubs  to  be  packed  full. 

No.  2  Packing  Stock  shall  be  reasonably  sweet  and  sound, 
and  may  be  packed  in  promiscuous  or  different  kinds  of  bar- 
rels, tubs  or  tierces,  without  being  parchment  paper  lined, 
and  may  be  packed  in  either  two-headed  or  cloth-covered 
barrels. 

No.  3  Packing  Stock  shall  be  a  grade  below  No.  2,  and 
may  be  off-flavored,  or  strong;  may  be  packed  in  any  kind  or 
kinds  of  packages. 

Mould.  There  shall  be  no  grade  for  butter  that  shows 
mould. 


DAIRY  LABORATORY  GUIDE  133 

STANDARDS  FOR  MILK  AND  MILK  PRODUCTS 

The  Association  of  State  and  National  Food  and  Dairy 
Departments  adopted  the  following  standards  for  milk  and 
milk  products  in  1908. 

MILK 

1.  Milk  is  the  fresh,  clean,  lacteal  secretion  obtained  by 
the  complete  milking  of  one  or  more  healthy  cows,  properly 
fed  and  kept,  excluding  that  obtained  within  fifteen  days 
before  and  ten  days  after  calving,  and  contains  not  less  than 
eight  and  one-half  (8.5)  per  cent  of  solids  not  fat,  and  not 
less  than  three  and  one-quarter  (3.25)  per  cent  of  milk  fat. 

2.  Blended  milk  is  milk  modified  in  its  composition  so 
as  to  have  a  definite  and  stated  percentage  of  one  or  more  of 
its  constituents. 

3.  Skimmilk  is  milk  from  which  a  part  or  all  of  the  cream 
has  been  removed,  and  contains  not  less  than  nine  and  one- 
quarter  (9.25)  per  cent  of  milk  solids. 

4.  Pasteurized  milk  is  milk  that  has  been  heated  below 
boiling,  yet  sufficiently  to  kill  most  of  the  active  organisms 
present,  and  immediately  cooled  to  50°  F.,  or  lower. 

5.  Sterilized  milk  is  milk  that  has  been  heated  to  the 
temperature  of  boiling  water,  or  higher,  for  a  length  of  time 
sufficient  to  kill  all  organisms  present. 

6.  Condensed  milk,  evaporated  milk  is  milk  from  which 
a  considerable  portion  of  water  has  been  evaporated,  and 
contains  not  less  than  twenty-eight  (28)  per  cent  of  milk 
solids,  of  which  not  less  than  twenty-seven  and  sixty-six  hun- 
dredths  (27.66)  per  cent  is  milk  fat. 

7.  Sweetened  condensed  milk  is  milk  from  which  a  con- 
siderable portion  of  water  has  been  evaporated  and  to  which 
sugar  (sucrose)  has  been  added,  and  contains  not  less  than 


134  DAIRY  LABORATORY  GUIDE 

twenty-eight  (28)  per  cent  of  milk  solids,  of  which  not  less 
than  twenty-seven  and  sixty-six  hundredths  (27.66)  per  cent 
is  milk  fat. 

8.  Condensed  skimmilk  is  skimmilk  from  wrhich  a  con- 
siderable portion  of  water  has  been  evaporated. 

9.  Buttermilk  is  the  product  that  remains  when  butter  is 
removed  from  milk  or  cream  in  the  process  of  churning. 

10.  Goat's  milk,  ewe's  milk,  etc.,  are  the  fresh,  clean, 
lacteal  secretions,  free  from  colostrum,  obtained  by  the  com- 
plete milking  of  healthy  animals  other  than  cows,  properly 
fed  and  kept,  and  conform  in  name  to  the  species  of  animals 
from  which  they  are  obtained. 

CREAM 

1.  Cream  is  that  portion  of  milk,  rich  in  milk  fat,  which 
rises  to  the  surface  of  milk  on  standing,  or  is  separated  from 
it  by  centrifugal  force,  is  fresh  and  clean,  and  contains  not  less 
than  eighteen  (18)  per  cent  of  milk  fat. 

2.  Evaporated  cream,  clotted  cream  is  cream  from  which 
a  considerable  portion  of  water  has  been  evaporated. 

MILK  FAT  OR  BUTTER-FAT 

1.  Milk-fat,  butter-fat  is  the  fat  of  milk,  and  has  a 
Reichert-Meissl  number  not  less  than  twenty-four  (24)  and  a 
specific  gravity  not  less  than  0.905-^ 

BUTTER 

1.  Butter  is  the  clean,  non-rancid  product  made  by  gath- 
ering in  any  manner  the  fat  of  fresh  or  ripened  milk  or  cream 
into  a  mass,  which  also  contains  a  small  portion  of  the  other 
milk  constituents,  with  or  without  salt,  and  contains  not  less 
than  eighty-two  and  five-tenths  (82.5)  per  cent  of  milk  fat. 
By  acts  of  Congress  approved  August  2,  1886,  and  May  9, 
1902,  butter  may  also  contain  added  coloring  matter. 


DAIRY  LABORATORY  GUIDE  135 

2.  Renovated  butter,  process  butter  is  the  product  made 
by  melting  butter  and  reworking,  without  the  addition  or  use 
of  chemicals  or  any  substances  except  milk,  cream,  or  salt, 
and  contains  not  more  than  sixteen  (16)  per  cent  of  water  and 
at  least  eighty-two  and  five-tenths  (82.5)  per  cent  of  milk  fat. 

CHEESE 

1.  Cheese  is  the  sound,  solid,  and  ripened  product  made 
from  milk  or  cream  by  coagulating  the  casein  thereof  with 
rennet  or  lactic  acid  with  or  without  the  addition  of  ripening 
ferments  and  seasoning,  and  contains,  in  the  water-free  sub- 
stance, not  less  than  fifty  (50)  per  cent  of  milk  fat.     By  act  of 
Congress,  approved  June  6,  1896,  cheese  may  also  contain 
added  coloring  matter. 

2.  Skimmilk  cheese  is  the  sound,  solid,  and  ripened 
product  made  from  skimmilk  by  coagulating  the  casein  thereof 
with  rennet  or  lactic  acid  with  or  without  the  addition  of 
ripening  ferments  and  seasoning. 

3.  Goat's  milk  cheese,  ewe's  milk  cheese,  etc.,  are  the 
sound,  ripened  products  made  from  the  milks  of  the  animals 
specified,  by  coagulating  the  casein  thereof  with  rennet  or 
lactic  acid  with  or  without  the  addition  of  ripening  ferments 

and  seasoning. 

ICE  CREAMS 

1.  Ice  cream  is  a  frozen  product  made  from  cream  and 
sugar  with  or  without  a  natural  flavoring,  and  contains  not 
less  than  fourteen  (14)  per  cent  of  milk  fat. 

2.  Fruit  ice  cream  is  a  frozen  product  made  from  cream, 
sugar,  and  sound,  clean,  mature  fruits,  and  contains  not  less 
than  twelve  (12)  per  cent  of  milk  fat. 

3.  Nut  ice  cream  is  a  frozen  product  made  from  cream, 
sugar,  and  sound,  non-rancid  nuts,  and  contains  not  less  than 
twelve  (12)  per  cent  of  milk  fat. 


136  DAIRY  LABORATORY  GUIDE 

MISCELLANEOUS  MILK  PRODUCTS 

1.  Whey  is  the  product  remaining  after  the  removal  of 
fat  and  casein  from  milk  in  the  process  of  cheese  making. 

2.  Kumiss  is  the  product  made  by  the  alcoholic  fermen- 
tation of  mare's  or  cow's  milk. 

COMPOSITION    OF    DAIRY    PRODUCTS    AND     BY- 
PRODUCTS 

The  following  are  a  number  of  average  compositions  for 
dairy  products  and  by-products  according  to  some  of  the  lead- 
ing authorities: 

Normal  milk Richmond. 

Water 87.10  per  cent. 

Fat 3.90  "       " 

Proteid 3.50  "       " 

Milk  sugar 4.75  "       " 

Ash.  .  .75  "      " 


Total 100.00 

Butter Richmond. 

Water 13.0   per  cent. 

Fat 83.5     "       " 

Proteid 1.0     "       " 

Milk  sugar 0.0     "       " 

Ash,  (salt,  etc.) 2.5     "      " 


Total 100.0 

Skimmilk Fleischmann. 

Water 90.30  per  cent". 

Fat 25  "  " 

Proteid 4.00  "  " 

Milk  sugar 4.70  "  " 

Ash..  .75  "  " 


Total 100.00 

Buttermilk Fleischmann. 

Water 91.24  per  cent. 

Fat 56  "       " 

Proteid 3.50  "       " 

Milk  sugar 4.00  "       " 

Ash..  .70  "       " 


Total .  .  .    100.00 


DAIRY  LABORATORY  GUIDE  137 

Whey Fleischmann. 

Water 93.31  per  cent. 

Fat 10  "  " 

Proteid 27  "  " 

Sugar 5.85  "  " 

Ash..  .47  "  " 


Total 100.00 

Sweetened  condensed  milk Fleischmann. 

Water 25.68  per  cent. 

Fat 10.99  "  " 

Proteid 12.33  "  " 

Sugar 48.66  "  " 

Ash.  .  2.34  "  " 


Total 100.00 

Unsweetened  condensed  milk Fleischmann. 

Water 48.59  per  cent. 

Fat 15.67  "  " 

Proteid 17.81  "  " 

Sugar..... 15.40  "  " 

Ash..  2.53  "  " 


Total 100.00 

CHEESE 

Cream Konig, 

Water 36.33  per  cent. 

Fat 40.71  "       " 

Proteid 18.84  "      " 

Sugar 1.02  "       " 

Ash..  3.10  "       " 


Total 100.00 

Full  Cream Konig. 

Water 38.00  per  cent. 

Fat 30.25  "       " 

Prcteid 25.35  "       " 

Sugar 1.43  "       " 

Ash..  4.97  "       " 


Total 100.00 

Skimmilk Konig 

Water 46.00  per  cent. 

Fat 11.65  "       " 

Proteid 34.06  "       " 

Sugar 3.42  «       " 

Ash..  4.87  "       " 


Total .  .  100.00 


133  DAIRY  LABORATORY  GUIDE 

Cheddar  cheese  (green) yan 

Water 36.80per  cent. 

Fat 33.75  «      « 

Proteid .  .  '. 23.75  "       " 

Sugar o!()0  "      " 

Ash 5.70  «       « 


Total 100.00 

Swiss Fleischmann. 

Water 36.1    per  cent. 

Fat 29.5     "       " 

Proteid '  28.0     "       " 

Sugar 3.3     "       « 

Ash 3.1     "       " 


Total 100.00 

^imburger Fleischmann. 

Water 35.7    per  cent. 

Fat 34.2     "       " 

Proteid 2 1.2     "       " 

Sugar 3.0     "      " 

Ash 2.9     "       " 


Tctal 100.00 


INDEX 


Acid,  lactic,  estimation  of,  18. 

Acid,  sulfuric,  adding  to  milk, 
50;  adding  to  cream,  58;  ef- 
fect of  strong,  53;  effect  of 
weak,  53;  effect  of  varying 
amounts  of,  52;  mixing  with 
sample,  50;  temperature,  55. 

Acidity,  test  in,  butter,  18; 
cream,  18;  milk,  18;  skim- 
milk,  18;  whey,  18. 

Alkaline  solution,  preparation 
of,  18;  tablets,  19. 

Babcock  test,  for  butter,  68; 
buttermilk,  56;  cheese,  66; 
condensed  milk,  70;  cream, 
58;  milk,  48;  skimmilk,  56; 
whey,  56. 

Bacteria,  in  milk  from  covered 
cans,  22,  30;  open  cans,  22, 
30;  pasteurized,  24;  ven- 
tilated stables,  22. 

Butter,  aroma,  123;  classifica- 
tion, 126,  130;  color,  92,  125; 
composition  of,  94,  135;  fla- 
vor, 124;  grading,  123,  130; 
grease,  127,  130;  manufacture 
of,  92;  moisture,  36;  over- 
working, 93,  104;  overrun, 
94;  packing,  94;  packing 
stock,  127, 129;  renovated,  40; 
salting,  93,  102,  126;  score 
card,  123;  texture,  125;  wash- 
ing, 100;  working,  93,  104. 

Butterfat,  in  butter,  68;  in  but- 
termilk, 56,  98;  in  cheese,  66; 
in  condensed  milk,  70;  in 
cream,  58,  112;  market-price, 
finding,  121;  melting  point 
of,  40;  in  milk,  48,  110;  read- 
ing the  test,  50;  in  skimmilk, 
56;  in  whey,  56. 

Butter  making,  92. 


Buttermilk,  butterfat  in,  56; 
composition  of,  133;  tem- 
perature, 98;  testing,  56;  re- 
moving, 93. 

Calibration  of  glassware,  44. 

Casein,  coagulation  with  acid, 
12;  coagulation  with  rennet, 
12;  digesting,  50,  56,  58; 
Micro-organisms  in,  16. 

Cheese,  test,  66;  Cheddar,  66, 
138;  Club,  66;  composition 
of,  136;  cream,  66,  134;  de- 
fined, 135;  Swiss,  66,  138; 
testing,  66. 

Churn,  care,  92;  filling,  92; 
washing,  92. 

Churning,  effect  of  temperature, 
98;  -influence  of  acidity,  96. 

Cream,  care  of,  7,  14,  90;  cool- 
ing, 28;  influence  of  grade 
on  butter  quality,  106;  meas- 
uring, 60;  market  value  of, 
121;  ripening,  92;  rule  for 
finding  amounts  of,  112,  118; 
rules  for  grading,  28;  screw, 
88;  standardizing,  118; 
straining,  92;  temperature, 
64,98;  testing,  58;  viscosity, 
60;  weighing,  58,  60. 

Creaming  methods,  90. 

Curd  test,  appearance,  16,  26; 
Wisconsin,  16. 

Dirt,  in  cream,  14;    milk,  14. 
Dividends,    figuring    creamery, 
121. 

Farrington  acid  test,  18. 

Fat  globules,  examination  of,  8; 

influence  of  heat  on,  10,  44; 

influence     of     cold     on,     10, 

44;  influence  of  chemicals  on, 

12;  size  of,  8. 


140 


DAIRY  LABORATORY  GUIDE 


Flavors  of  dairy  products,  32, 
124. 

Glassware,  c  a  1  i  b  r  a  ting,  44 ; 
cleaning,  45. 

Ice  cream,  defined,  135;  figur- 
ing value  of,  116. 

Indicators,  acid  test,  18; 
chromate,  38;  phenolphtha- 
lein,  18;  preparation  of,  18; 
salt  test,  38. 

Lactometer,  application  of,  72; 
Quevenne,  72. 

Manns'  acid  test,  18. 

Marketing  dairy  products,  109. 

Milk,  acidity  of,  18;  bacteria 
in,  14;  bottles,  14;  casein  in, 
12,  50;  colostrum,  10  ;  clean, 
24;  color  of,  8,  10;  composi- 
tion of,  136;  condensed,  70; 
dirt  in,  14;  effects  of  venti- 
lation, 22;  fermentations  of, 
16;  microscopic  examination 
of,  8;  preserving,  43;  sam- 
pling, 43;  sampling  with 
pipette,  45;  solids  in,  73; 
souring  of,  18,  26,  44;  specific 
gravity  of,  72;  standards  for, 
133;  standardizing  of,  118; 
value  of  market,  110. 

Milk  pails,  14,  25. 

Margarine,  test  for,  40. 

Moisture  test,  butter,  36; 
cheese,  36;  margarine,  36; 
tester,  36. 

Mottles  in  butter,  105. 

Odors  in  dairy  products,  16,  22, 

24,  28,  30,  32,  34. 
Over-run,    formula,   95;     value, 

94. 


Package  butter,  94,  126. 
Pasteurizing  milk,  24. 
Pipette,  size,  45;    using,  48. 

Rennet,  action  of,  12;  tempera- 
ture on,  26,  92. 

Salt,  in  butter,  38,  126;  in 
cheese,  38;  in  margarine,  38. 

Samples,  churned,  44;  frozen, 
44;  preserving,  43;  sour,  44; 
taking,  43. 

Scoring  butter,  123. 

Sediment  tester,  14. 

Separators,  care  of,  75;  flush- 
ing, 80;  screw  in,  88;  speed 
of,  86;  temperature  for,  84; 
washing,  82. 

Specific  gravity  of  milk,  72. 

Standardizing  dairy  products, 
118,  133. 

Testing,  butter,  68;  cheese,  66; 
condensed  milk,  70;  cream, 
58;  milk,  48;  separators,  78; 
skimmilk,  56;  speed  of 
separator,  86;  speed  tester. 
62;  whey,  56. 

Texture,  butter,  125. 

Total  solids,  milk,  72. 

Temperature,  effects  on  lacto- 
meter reading,  72;  effects  on 
time  to  churn,  92,  98;  effects 
on  reading  test,  54;  ef- 
fects on  action  rennet,  92; 
effects  on  hand  separator,  84. 

Weighing,  cream  samples,  60; 

cheese,  66;    condensed  milk, 

70. 
Water,  impure,  effect  on  dairy 

products,  34;    temperature  in 

testing,  54. 


STANDARD  BOOKS  FOR  FARMS 
AND  FARM  SCHOOLS 

We  can  supply  any  book  published  on  General  Farming, 
Gardening,  Dairy,  Live  Stock,  Horticulture,  Forestry,  Soils, 
Poultry,  Bees,  etc.  All  inquiries  and  orders  for  Farm  Books  will 
receive  prompt  attention. 


fVnnc 

crops 


Beginnings"*  Animal  Husbandry 

By  Prof.  C.  S.  Plumb,  of  the  Ohio  State  Univer- 
sity College  of  Agriculture.  Author  of  "Types 
and  Breeds,"  etc.  It  teaches  in  a  very  interest- 
ing way  what  every  farmer  and  farm  boy  ought 
to  know  about  types  and  breeds,  judging,  breed- 
ing, feeding  and  care  of  farm  animals  and  poul- 
try. No  book  like  it  has  ever  been  published. 
393  pages;  216  illustrations.  Cloth  bound,  $1.25; 
postage  12c  extra. 


.  new  standard  book  by  A. 
D.  Wilson,  Minn.  College  of 
Agr.,  and  C.  W.  Warburton,  U.  S.  Dept.  of  Agr., 
on  the  best  methods  of  growing,  harvesting  and 
marketing  farm  crops;  seed  selection;  fertilizers; 
cost  of  production;  rotations;  and  weeds. 
Handsomely  bound;  544  pages;  160  illustrations. 
A  practical  book  by  practical  men.  Cloth  bound, 
$1.50;  postage  17c  extra. 

Soils  and  Soil  Fertility 

nical  discussion,  by  Profs.  A.  R.  Whitson  and 
H.  L.  Walster,  of  the  Wis.  College  of  Agr.,  pre- 
senting the  foundation  principles  of  soil  manage- 
ment. It  tells  clearly  how  to  make  simple  tests 
of  soils  to  discover  their  needs;  how  to  fertilize, 
till,  and  otherwise  handle  different  types  of  soil, 
as  sandy,  marsh  and  clay  soil.  It  will  answer 
your  perplexing  soil  questions.  315  pages;  well 
illustrated;  nicely  bound.  Cloth,  $1.25;  postage  12c  extra. 


SOILS 


Make  all  Remittances  by  Postoffice  or  Express  Orders,  or 
New  York,  Chicago,  or  St.  Paul  Drafts. 

Webb  Publishing  Co.,        St.  Paul,  Minn. 


AGRICULTURAL 
ENGINEERING 


Agricultural  Engineering 

son,  Iowa  State  College  of  Agriculture.  (In 
preparation.)  A  complete  and  practical  handy 
manual  and  text  book  of  all  engineering  prob- 
lems of  the  farm,  including  land  surveying, 
drainage,  irrigation,  roads,  farm  machinery  and 
farm  motors,  farm  buildings,  and  sanitation.  It 
will  be  a  most  effective  aid  in  farm  management. 
About  500  pages;  over  300  illustrations;  a  hand- 


some book.     Cloth,  $1.50;  postage  15c  extra. 

Popular  Fruit  Growing 

Green,  Minn.  College  of  Agri.  A  very  popular 
treatise  on  horticultural  methods  and  practices. 
Gives  principles  of  successful  orchard  manage- 
ment and  small  fruit  culture,  fruits  adapted  to 
each  state,  how  to  ward  off  insects  and  diseases, 
harvesting  and  marketing  methods.  A  standard 
text  in  many  schools.  300  pages;  profusely  il- 
lustrated. Cloth,  $1.00;  postage  12c  extra. 


GROWING. 


Vegetable  Gardening  ,^es 

Horticulture,  Minn.  College  of  Agri.  A  handy 
manual  on  the  growing  of  all  kinds  of  vegetables 
for  home  use  and  for  the  market.  It  is  used  as  a 
practical  school  text  book  and  is  indispensable  to 
farmers  and  gardeners  everywhere.  122  il- 
lustrations; 252  pages.  Twelfth  edition.  Cloth 
$1.00.  Paper  cover,  50  cts.  Postpaid. 


Agriculture   for  Young   Folks 

By  A.  D.  Wilson,  Supt.  of  Farmers'  Institutes 
and  Agricultural  Extension,  University  of  Minn., 
and  E.  A.  Wilson.  This  is  the  most  practical 
elementary  agricultural  text  book  for  rural  and 
graded  schools  ever  published.  It  presents  the 
elementary  principles  of  agriculture  through  les- 
sons based  on  practical  farm  problems.  340 
pages;  well  illustrated;  cloth  bound.  Price  $1.00. 
By  mail  10  cents  extra. 


Webb  Publishing  Co.,        St.  Paul,  Minn. 


Ponltrv  Manual  A  standard 

rouiiry  manual  for  succekSSfu]  poul_ 

try  keeping,  by  F.  L.  Sewell  and  Ida  E.  Til- 
son,  both  well  known  authorities  on  domestic 
fowls  and  their  keeping.  Selection  and 
breeding  for  egg  production,  rations  and 
methods  of  feeding  and  general  care  of  fowls 
are  emphasized.  Well  illustrated;  148  pages. 
Cloth,  50  cents.  Paper  covers,  25  cents. 


The  Country  Kitchen 


A   book    of 
household 

recipes,  all  contributed  by  farmers'  wives  and 
daughters,  readers  of  The  Farmer.  This  is  a 
choice  collection  of  over  900  of  the  best  recipes 
which  have  been  received.  It  has  been  printed 
in  many  editions,  and  istoday  the  most  popular 
book  of  its  class  published.  It  is  sure  to  prove 
a  most  helpful  servant  in  your  kitchen.  Cloth 
bound,  50  cents.  Paper  covers,  25  cts.  Postpaid. 


Weeds  and  How  to  Eradicate 

**y  Prof<  Thomas  Shaw,  author  of  nu- 
merous agricultural  works.  In  this  book 
simple  but  practical  means  of  distinguishing 
different  weeds  are  taught,  the  manner  of  growth 
of  each  explained,  and  the  best  methods  for  their 
eradication  and  control  advised.  208  pages;  il- 
lustrated. Cloth  bound,  50  cts.  Paper  cover,  25 
cents.  Postpaid. 


Quack  Grass  Eradication 

practical  farmer  who  has  worked  out  a  system  of 
soil  treatment  which  results  in  a  permanent  de- 
struction of  quack  grass.  It  is  not  necessary  to 
lose  a  crop  by  this  method,  nor  are  expensive 
tools  needed.  The  principles  involved  are  plainly 
stated  and  the  process  itself  in  not  complex. 
This  book  should  be  in  the  hands  of  every  farm- 
er on  whose  farm  quack  grass  is  spreading. 
Cloth  bound,  $1.00.  Postpaid. 


«<> 

~$p 


Webb  Publishing  Co.,       St.  Paul,  Minn. 


f\i 
OI 


Evergreens  and  How  to  Grow 

Tll6ni  ^  ^'  ^'  Harrison.  The  practical 
1 11  will  va]ue  of  evergreens  for  windbreaks 
and  shelterbel  cs  and  for  ornamental  purposes 
makes  this  book  of  value  to  every  farmer  of 
the  United  States.  Evergreens  are  not  hard 
to  grow,  but  unless  certain  details  are  looked 
after,  failure  is  likely.  Mr.  Harrison  tells  very 
plainly,  from  his  extensive  experience,  the 
correct  treatment  to  follow.  Varieties  illus- 
trated. 100  pages.  Paper  cover,  25c.  Postpaid. 

and  Civil   Government. 

Illustrated     and    made 


plain.  Everyone,  at  some  time  or  other,  is  likely 
to  require  some  knowledge  of  rules  of  order.  But 
few  are  willing  to  take  the  time  or  trouble  to 
master  all  the  fine  points.  This  book  puts  the 
rules  in  so  simple  and  brief  a  manner  that  all  the 
knowledge  that  one  needs  to  know  for  the  con- 
duct of  the  average  meeting  is  easily  grasped. 
The  fundamentals  of  Civil  Government  are  also 
made  exceedingly  plain.  Handy  size;  110  pages; 
Cloth  bound,  50c.  Postpaid. 


illustrated. 


GOLDMINE 


The  Gold  Mine  in  the  Front 

Vflfd  ^  ^'  ^'  Harrison.  This  is  an  ex- 
I  CU  U  tremely  interesting  book  describing 
the  improvement  of  the  home  grounds.  Mr. 
Harrison  is  a  well-known  floriculturist,  who 
tells  in  a  very  interesting  style  of  the  varieties 
of  flowers  and  vines  to  grow,  how  to  grow 
them,  and  their  proper  arrangement  for  the 
best  effect.  A  delightful  book  for  flower  lov- 
ers. 280  pages;  illustrated.  Cloth  bound, 
$1.00.  Postpaid. 

This 
book 


Vacant  Government  Lands 

gives  the  latest  authentic  information  about  va- 
cant government  land  and  how  it  may  be  home- 
steaded.  It  locates  all  vacant  land  by  counties 
in  each  state,  gives  a  digest  of  the  homestead 
laws,  and  many  necessary  and  valuable  facts 
needful  in  making  a  location.  Latest  edition. 
Sent  postpaid  to  any  address  for  25c. 


Webb  Publishing  Co.,        St.  Paul,  Minn. 


UNIVERSITY   OF   CALIFORNIA 
BRANCH    OF    THE    COLLEGE    OF    AGRICULTURE 

THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


3m-9,'30 


Dairy  lab 
S  51 


M3 


LIBRARY,  BRANCH  OF  THE  COLLEGE  OF  AGRICULTURE,  DAVIS 


